MS to release CEdg[e] with IE for Win7+

https://www.theverge.com/2019/5/6/18...res-build-2019

Wacky stuff. They won't let Win7/8 users install the official
Windows browser, but they'll provide Google's browser. And now
they plan to build in a copy of IE to accommodate business
users. But every OS already has IE. ?? And they seem to
already be building in/keeping Edge itself as part of the
browser. So do Win7 users also get Edge.

In any case, anyone who wants to experiment with a
browser that incorporates spyware from 2 companies instead
of just one, can now do it.

For webmasters, as I understand it, the UA is "Edg"
instead of "Edge". Personally I block Edge rather than buy
Win10 and spend time writing webpage code for it, but I
expect I'll just allow Edg, on the assumption that it's
really just Chrome, which uses the same web standards
as Firefox. (If that's not the case then MS are going to
have a lot of unhappy Edg users.)

To complicate matters, CEdg[e] reportedly has a function
to change UA strings on a per-site basis. So the browser
that used to own the Internet will now actually be a pile
of most of the browser on the Internet, and will spoof its
UA in order to make webpages display properly.

I wasn't clear on that part of the story. At least at one
point MS were using a configuration file to predetermine
what UA it would present to major websites.

https://winaero.com/blog/microsoft-e...ts-user-agent/

If they keep that up it could become a kind of arms war,
as MS tries to make Cedg work while companies like Google
try to thwart them:

https://www.bleepingcomputer.com/new...not-supported/

But the info I'm finding is mostly a couple of months old.

Mayayana wrote:

https://www.theverge.com/2019/5/6/18...res-build-2019

Wacky stuff. They won't let Win7/8 users install the official Windows
browser, but they'll provide Google's browser.

It is not "Google's browser". Microsoft gave up on their Edge rendering
engine and switched to use the Blink engine. That does not make Edge
"Google's browser". Just the rendering engine got replaced. There are
LOTS of web browers that use the Blink rendering engine (that Chromium
hence Chrome uses), like Opera, Vivaldi, Brave, Blisk, Colibri, Epic,
Iron, Dragon, Avast, Samsung, Amazon, Yandex, Qihoo, Torch, and lots
more. Some of the Chrome variants are MORE secure and private than
Google's Chrome. Changing to a different rendering engine does not
dictate the remaining behavior of a web browser. Wearing different
eyeglasses does not change if you stand or squat to pee.

And now they plan to build in a copy of IE to accommodate business
users. But every OS already has IE.

Sounds a lot like the IE Tab extension for Google Chrome that provided
an IE Mode tab.

https://chrome.google.com/webstore/d...enadd?hl=en-US

Rendering compatibility is not the same as providing the entire web
browser. Microsoft intent has been to kill off Internet Explorer. If
they add a rendering mode in CEdge then they can completely eradicate it
from Windows 10; however, there are still a lot of HTAs (HTML
Applications) that rely on the IE libs, so the libs will probably stick
around but the chrome app (not Chrome, but chrome which means everything
of the web browser outside the document window) will disappear.

And they seem to already be building in/keeping Edge itself as part of
the browser. So do Win7 users also get Edge.

I doubt it. Main support for Windows 7 ended back in 13-Jan-2015. That
allows for feature updates. Extended support ends in 14-Jan-2020, but
that's just for security updates. I suspect by the time CEDGE shows up
in Windows 7 will be after all support dies for Windows 7.

To complicate matters, CEdg[e] reportedly has a function to change UA
strings on a per-site basis. So the browser that used to own the
Internet will now actually be a pile of most of the browser on the
Internet, and will spoof its UA in order to make webpages display
properly.

Since sites still have code branches based on the visiting web browser,
changing the UA string for the IE Mode tab would be not only necessary
but expected. There would be no point in spoofing the IE Mode tab as
the Chromium browser since the non-IE Mode tabs would already be the
Chromium browser.

However, even Microsoft has stated that using the UA string is a
deprecated method to detect which web browser is visiting a site.
Instead the site should query the client as to its capabilities to know
if the site can use them or reject the client. ANY web client can spoof
the UA string, not just CEDGE for its IE Mode tab. This isn't new. Yet
Microsoft then adds UA spoofing to CEDGE. Well, it really isn't
spoofing in the normal sense because you are visiting a site that is
using the IE rendering engine (Trident) rather than visiting with a
different engine but pretending it's something else.

I wasn't clear on that part of the story. At least at one
point MS were using a configuration file to predetermine
what UA it would present to major websites.

Just sounds like a site preference that gets stored.

https://winaero.com/blog/microsoft-e...ts-user-agent/

That requires cooperation by the server. If the server admins decide
not to waste their time coddling to one web client author, I don't see
that scheme evolving into the norm.

If they keep that up it could become a kind of arms war, as MS tries
to make Cedg work while companies like Google try to thwart them:

https://www.bleepingcomputer.com/new...not-supported/

I wonder if that has more to do with the Google Docs extensions (Docs,
Sheets, etc) that get installed into Google Chrome. I don't bother with
those, and when I find them in Google Chrome they get removed. I don't
use Google Docs (their web service), but if I did then I would just use
what their webclient supports and not what additional features are
available via extensions which may not exist in Google Chrome and won't
be available if a different web client is used to connect to their web
service. Just because a web client switches to Blink does not mandate
that it supports the WE (WebExtension) extensions that Chrome supports.

"VanguardLH" wrote

| Wacky stuff. They won't let Win7/8 users install the official Windows
| browser, but they'll provide Google's browser.
|
| It is not "Google's browser". Microsoft gave up on their Edge rendering
| engine and switched to use the Blink engine.

Yes. That was a bit of poetic license for effect. I'm
not sure I could explain that to you. It requires sense
of humor.

But then there's also the issue of Chromium being
Google's project. Android is OSS. Chromium is OSS.
But Google has become very clever at making OSS
closed. I once tried SRWare Iron, which claims to
be a private version of Chromium, with all the Google
spyware removed. As soon as it started up the first
time it tried to go to start-iron.com without asking.
When that failed it tried to go to Google -- exactly
what the SRWare website says it won't do.

So I view anything with Chromium as being a
Google corruption. I don't see any reason to fool
around with it. Like trying to have privacy in Win10,
it's not designed with integrity.


| I wasn't clear on that part of the story. At least at one
| point MS were using a configuration file to predetermine
| what UA it would present to major websites.
|
| Just sounds like a site preference that gets stored.
|

No. That's not what I said. It was an actual config file
downloaded with the browser. Apparently you didn't read
the winaero link. But it's not clear whether that's still
operational.

|
https://winaero.com/blog/microsoft-e...ts-user-agent/
|
| That requires cooperation by the server. If the server admins decide
| not to waste their time coddling to one web client author, I don't see
| that scheme evolving into the norm.
|

Huh? You seem to be misunderstanding. This is about the
UA a browser sends. You may have heard that UA is out
of style but it's still very much relevant. Sites increasingly
use script to do things like find out how big your screen is,
then assign image sizes accordingly. But there are still
rendering differences that must be dealt with. If you look at
the code of most commercial sites you'll see code designed
to accommodate different IE versions. It's not about
coddling. It's about not wanting to lose customers.

I do the same on my own site. IE renders differently from
other browsers. And different versions of IE render differently.
I'm not clear about the original Edge. I don't use Win10 so
I've never tried it and don't support it. But I serve different
pages to IE vs Chrome/FF/Safari. If I didn't then the pages
would display properly. Some of it is extreme. For instance,
older versions of IE can't handle a CSS flyout menu. If I
didn't give them a different page then the menus
wouldn't work. The reason you see broken websites (if you
do) is because the webmasters are not paying attention
to UAs.

| If they keep that up it could become a kind of arms war, as MS tries
| to make Cedg work while companies like Google try to thwart them:
|
|
https://www.bleepingcomputer.com/new...not-supported/
|
| I wonder if that has more to do with the Google Docs extensions (Docs,
| Sheets, etc) that get installed into Google Chrome.

I didn't know about that. Are you saying Google Docs
only works in Chrome, not in Safari, Edge or FF? If it
works in any of them then there's no reason for Google
to show an "outdated browser" message in CEdg.

Mayayana wrote:
https://www.theverge.com/2019/5/6/18...res-build-2019

Wacky stuff. They won't let Win7/8 users install the official
Windows browser, but they'll provide Google's browser. And now
they plan to build in a copy of IE to accommodate business
users. But every OS already has IE. ?? And they seem to
already be building in/keeping Edge itself as part of the
browser. So do Win7 users also get Edge.

But there's a strategy here, nonetheless.

This means all the maintenance of IE can be rolled into the
one package. There would no longer be a separate IE team
and an MSEdge team.

And that's one of the reasons for the backport, so when
they tell business "hey, IE is gone man", business
will have Chromge to cover off the complaints that
business users were abandoned.

The sooner they can release this bloated thing, the
clock can start ticking for rolling the IE team into
MSEdge team.

And the project will probably also be a poster child
for "Universal App" or something, to show how one
code package can be used more than one place. They
like to do that with some of the things they build,
make poster children out of them.

Who knows, in the end, perhaps only the rendering engine
is the part they keep from the original Chrome. As too
much of the other fluff won't fit.

Paul

On 6/20/19 8:51 AM, Mayayana wrote:

[snip]

For webmasters, as I understand it, the UA is "Edg"
instead of "Edge". Personally I block Edge rather than buy
Win10 and spend time writing webpage code for it,

I might have done the same, but I got a free upgrade from Win 8.1, which
I didn't want either.

but I
expect I'll just allow Edg, on the assumption that it's
really just Chrome, which uses the same web standards
as Firefox. (If that's not the case then MS are going to
have a lot of unhappy Edg users.)

So far, it seems to be like Chrome, including spinboxes on INPUT TYPE=number

[snip]

BTW, one feature I'd like to see is the ability to add things to the
right-click menu (HTML MENU and MENUITEM tags), however only Firefox
supports this.

--
Mark Lloyd
http://notstupid.us/

"The truth cannot be asserted without denouncing the falsehood." [Leslie
Stephen]

"Paul" wrote

| This means all the maintenance of IE can be rolled into the
| one package. There would no longer be a separate IE team
| and an MSEdge team.
|
| And that's one of the reasons for the backport, so when
| they tell business "hey, IE is gone man", business
| will have Chromge to cover off the complaints that
| business users were abandoned.
|

It doesn't work that way. Business have sites using
ActiveX, HTAs, etc. That's why they need IE. Since
it's already on Win7/8 it seems unlikely that they'll
change that, or port the Edge part. That would require
a significant reworking of system files on systems they
no longer want to deal with.

I'm guessing Cedg on 10 will be "everything but the
kitchen sink" while CEdg on 7/8 will be just MS Chrome.

In any case, it'll be fun coming up with names for
this new Crudge.

Mayayana wrote:

VanguardLH wrote

Wacky stuff. They won't let Win7/8 users install the official Windows
browser, but they'll provide Google's browser.

It is not "Google's browser". Microsoft gave up on their Edge rendering
engine and switched to use the Blink engine.

Yes. That was a bit of poetic license for effect. I'm not sure I could
explain that to you. It requires sense of humor.

With your subsequent berating of Google (and Microsoft), sure didn't
appear to be humor.

But then there's also the issue of Chromium being Google's project.
Android is OSS. Chromium is OSS. But Google has become very clever at
making OSS closed.

Chromium is all open source. Google Chrome is Chromium with the
addition of Google proprietary cod.

I once tried SRWare Iron, which claims to be a private version of
Chromium, with all the Google spyware removed. As soon as it started
up the first time it tried to go to start-iron.com without asking.
When that failed it tried to go to Google -- exactly what the SRWare
website says it won't do.

Sounds more like an SRware thing in the code they added to Chromium.

https://winaero.com/blog/microsoft-e...ts-user-agent/

That requires cooperation by the server. If the server admins decide
not to waste their time coddling to one web client author, I don't
see that scheme evolving into the norm.

Huh? You seem to be misunderstanding. This is about the
UA a browser sends.

Yep, and then how the server responds in its decision tree on how to
handle that web client under that identification. Just because you
spoof Chrome or Firefox to send a UA string that says your web client is
IE doesn't mean the site has to bother presenting web pages designed for
IE. If they don't want to support IE (or CEdg), they can inform you,
reject the connection, or take whatever action they want, or do nothing
and present you with a web page that renders just fine under Chrome
(i.e., not have a decision tree that delivers different web pages).

You may have heard that UA is out
of style but it's still very much relevant.

Still used is not the same as not deprecated.

https://tools.ietf.org/html/draft-da...tion-header-00

Deprecation means eventual removal, like old browned lettuce. My
recollection was Microsoft declared UA should be deprecated about 2014.

https://developer.mozilla.org/en-US/...the_user_agent

Are you trying to check for the existence of a specific feature?
You should never do user agent sniffing. There is always the
alternative of doing feature detection instead.

Do you want to provide different HTML depending on which browser is
being used?
This is usually a bad practice ...

https://developer.mozilla.org/en-US/...orID/userAgent

The specification asks browsers to provide as little information via
this field as possible. Never assume that the value of this property
will stay the same in future versions of the same browser. Try not to
use it at all, or only for current and past versions of a browser. New
browsers may start using the same UA, or part of it, as an older
browser: you really have no guarantee that the browser agent is indeed
the one advertised by this property.

Also keep in mind that users of a browser can change the value of this
field if they want (UA spoofing).

Browser identification based on detecting the user agent string is
unreliable and is not recommended, as the user agent string is user
configurable.

https://www.bleepingcomputer.com/new...not-supported/

| I wonder if that has more to do with the Google Docs extensions (Docs,
Sheets, etc) that get installed into Google Chrome.

I didn't know about that. Are you saying Google Docs only works in
Chrome, not in Safari, Edge or FF? If it works in any of them then
there's no reason for Google to show an "outdated browser" message in
CEdg.

Perhaps when I installed Google Chrome, or later when it updated, I
found the Google Docs, Google Sheets, Google Slides, and Google Drive
extensions. I never went to the Chrome store to install those
extensions.

https://chrome.google.com/webstore/d...nilnnbdlolhkhi

Could be they're just to let the user edit their docs while offline (no
Internet connectivity), but that means the docs would have to be locally
cached.

https://support.google.com/docs/answ...DDesktop&hl=en

Okay, so it's some kind of caching scheme. However, I do know there are
Google sites that ONLY work with Google Chrome. I don't remember what
was the Google site, but it announced it was usable only with Chrome.
They see you are visiting with a non-Chrome web client and then refuse
to function properly. They're Google Chrome-only sites: some service
Google provides where they demand you use Chrome. That likely means
Chrome (the proprietary part Google adds to Chromium) has some features
that are reserved for use only with some Google services.

The Google service knows about secret code in Google Chrome. This is
very much like when Microsoft used secret code in their Office suite to
allow their software to perform functions not available to anyone else.

The first Mozilla article on the UA header notes (and why UA detection
fails versus feature detection):

A good current example of feature detection is as follows. Recently,
Chrome added experimental lookbehind support to regular expressions,
but no other browser currently supports this. So, you might
incorrectly assume you should do this:

if (navigator.userAgent.indexOf("Chrome") !== -1){
// YES, the user is suspected to support look-behind regexps
} else { /*put your old fall back code here*/ }

Google is notorious for adding and then deleting experimental features.
Same for a lot of their [experimental] services that were eventually
discontinued. Since it was an experimental feature of Chrome, Google
has no reservation to remove it. I remember lots of options in
chrome://flags that were very handy disappearing later and removing that
handy and often essential feature (and you were lucky if you found an
extension to bring it back). All flags in Chrome are deemed
experimental, so relying on them is risky. Same for experimental
features within Chrome. Using the UA string after Google removes a
feature means you think Chrome can do the feature but it's gone, so the
UA detection results in using the wrong page code for the current
version of Chrome that is visiting your site.

"VanguardLH" wrote

| you really have no guarantee that the browser agent is indeed
| the one advertised by this property.
|

No. But that's up to the end user. If they have IE and
pretend to be FF they're only causing problems for themselves.
Virtually all webmasters still use UA. It would becrazy not to.
The feature sniffing you're talking about 1) requires script
enabled and 2) as I said before, is for finding things like
screen size.

Microsoft have reason to downplay UA because they're
embarassed by what a mess their browsers are. They want
people to assume Edge is like FF and Chrome. They also
add those to their UA for compatibility. But from what I've
heard, it's not like FF and Chrome. So for webmasters to
ignore the Edge UA is to damage compatibility on their site.

In any case, it's up to you. I use my own system to make
sure my pages look the same in all browsers and function
without script in all browsers but IE. I use testing and UAs
to do that. The UAs are known. Companies don't just change
them willy nilly. If you have a website you can do as you
like. It will probably work OK if I visit, though since I
disable script your "feature sniffing" won't work and I may
find your site to be broken. Maybe you don't care. That's
fine. I'm old school. I like to try to make my pages work in
all browsers predictably and without special requirements.

In message , VanguardLH
writes:
Mayayana wrote:
[]
If they keep that up it could become a kind of arms war, as MS tries
to make Cedg work while companies like Google try to thwart them:


https://www.bleepingcomputer.com/new...cs-says-chromi
um-based-microsoft-edge-is-not-supported/

I wonder if that has more to do with the Google Docs extensions (Docs,
Sheets, etc) that get installed into Google Chrome. I don't bother with
those, and when I find them in Google Chrome they get removed. I don't
[]
How do you find them, and when you have, how do you remove them?

Feel free to say the answer(s) is/are too complicated for me to
understand - in fact if they're at all complex, please do, rather than
try to give a lengthy explanation. I'm only asking out of _mild_
curiosity.
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

[What's your guilty pleasure?] Why should you feel guilty about pleasure? -
Michel Roux Jr in Radio Times 2-8 February 2013

"Mayayana" on Thu, 20 Jun 2019 09:51:23
-0400 typed in alt.windows7.general the following:
https://www.theverge.com/2019/5/6/18...res-build-2019

Wacky stuff. They won't let Win7/8 users install the official
Windows browser, but they'll provide Google's browser. And now
they plan to build in a copy of IE to accommodate business
users. But every OS already has IE. ?? And they seem to
already be building in/keeping Edge itself as part of the
browser. So do Win7 users also get Edge.

In any case, anyone who wants to experiment with a
browser that incorporates spyware from 2 companies instead
of just one, can now do it.

For webmasters, as I understand it, the UA is "Edg"

For the non-technically proficient, What is UA?
--
pyotr filipivich
Next month's Panel: Graft - Boon or blessing?

In article , pyotr
filipivich wrote:


For webmasters, as I understand it, the UA is "Edg"

For the non-technically proficient, What is UA?

user agent

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/User-Agent
The User-Agent request header contains a characteristic string
that allows the network protocol peers to identify the application
type, operating system, software vendor or software version of
the requesting software user agent.

J. P. Gilliver (John) wrote:

In message , VanguardLH
writes:
Mayayana wrote:
[]
If they keep that up it could become a kind of arms war, as MS tries
to make Cedg work while companies like Google try to thwart them:


https://www.bleepingcomputer.com/new...cs-says-chromi
um-based-microsoft-edge-is-not-supported/

I wonder if that has more to do with the Google Docs extensions (Docs,
Sheets, etc) that get installed into Google Chrome. I don't bother with
those, and when I find them in Google Chrome they get removed. I don't
[]
How do you find them, and when you have, how do you remove them?

Feel free to say the answer(s) is/are too complicated for me to
understand - in fact if they're at all complex, please do, rather than
try to give a lengthy explanation. I'm only asking out of _mild_
curiosity.

Just go to the Chrome store and search on Google Docs Offline. They
install and remove just like other extensions.

Gave the URL in the Chrome store for the extension bundle in the
subthread where I'm replying to Mayayana.

pyotr filipivich wrote:

For the non-technically proficient, What is UA?

It's a header the web client sends to identify itself the server, but it
can be spoofed.

https://en.wikipedia.org/wiki/User_agent
https://developer.mozilla.org/en-US/...ers/User-Agent
https://www.howtogeek.com/114937/htg...er-user-agent/

To see what the UA header's value your web client sends to the server,
you can use a test site that reports back to what it was, like:

https://www.whatismybrowser.com/dete...-my-user-agent

In message , VanguardLH
writes:
J. P. Gilliver (John) wrote:

In message , VanguardLH
writes:
Mayayana wrote:
[]
If they keep that up it could become a kind of arms war, as MS tries
to make Cedg work while companies like Google try to thwart them:


https://www.bleepingcomputer.com/new...cs-says-chromi
um-based-microsoft-edge-is-not-supported/

I wonder if that has more to do with the Google Docs extensions (Docs,
Sheets, etc) that get installed into Google Chrome. I don't bother with
those, and when I find them in Google Chrome they get removed. I don't
[]
How do you find them, and when you have, how do you remove them?

Feel free to say the answer(s) is/are too complicated for me to
understand - in fact if they're at all complex, please do, rather than
try to give a lengthy explanation. I'm only asking out of _mild_
curiosity.

Just go to the Chrome store and search on Google Docs Offline. They
install and remove just like other extensions.

Gave the URL in the Chrome store for the extension bundle in the
subthread where I'm replying to Mayayana.

Ah, that would be
https://chrome.google.com/webstore/d...ne/ghbmnnjooek
pmoecnnnilnnbdlolhkhi, I presume. I'm looking at that in my Chrome now,
and it shows the Add to Chrome button, so I presumably don't have it
installed; when you sad those extensions "get installed", I thought you
meant they did so without the user doing anything ("when I find them").
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

I'd rather trust the guys in the lab coats who aren't demanding that I get up
early on Sundays to apologize for being human.
-- Captain Splendid (quoted by "The Real Bev" in mozilla.general, 2014-11-16)

"pyotr filipivich" wrote
|
| For the non-technically proficient, What is UA?

Sorry. userAgent. I just get tired of writing the whole
thing and figured that people know what it is or could deduce.
In most browsers you can set it as you like. (In IE it's difficult,
requiring a number of Registry tweaks. I'm not sure if even
that works in later versions.) There are also extensions that
can do it.

Though it can be a bit tricky. In FF, at least, the
browser UA doesn't seem to be the same as the script-
returned UA. When you visit a site, the browser sends a
header, including the UA. But javascript can also query
the UA. In my experience, both need to be altered.

In the past it's also been common to put ads and other
info in UAs. Microsoft used to add the installed version of
..Net.... Search bots identify themselves... Sometimes
download programs will add their name.

This goes back to the early days of browsers. The idea
was to let the website know what software and OS was
handling the page request. It might have started out of vanity;
I don't know. But it's historically been used to accommodate
different browsers. For instance, I'm using New Moon on XP
as well as FF 52.9. I send a UA like so:

Mozilla/5.0 (Windows NT 6.1; WOW64; rv:64.0) Gecko/20100101 Firefox/64.0

At some point I'll update it. I set the UA
to something recent, so that dingbat websites won't
complain or even refuse to load because they think
my browser is more than a month old. Google is one
of the worst. They've become like Microsoft used to
be. But it's not just Google. Many websites have
become javascript software, with 1+ MB of script
loading, and very little actual HTML. what used to be
a webpage is now a large software program, with dynamic
display, tracking, custom ads, etc.

The webmasters for those sites are often
trying to look clever, loading things like jquery and
wanting to use the very latest functionality. They
usually don't even know what they're doing. They just
share code snippets among themselves for doing clever
things.
In that commercial, heavily scripted environment
the focus has changed from accommodating as many
browsers as possible to demanding the most recent
browser. Back 15 years ago, hotshot web designers
used to be mocked for putting notes on their sites
that said things like: "Best viewed with Internet
Explorer 5.5". They were vain dandies who wanted to
show off their talents, even if no one could load their
page properly. Today it's reversed: "You want to see
our page? Get the latest browser." "Sorry, but your
browser is unacceptable for what we want to do."

Some sites are so messed up I never get them to work.
I have to visit Netflix on my computer where I allow
bad security because it won't work otherwise. and they
change the whole thing frequently! I have recent FF and
allow script, but still Netflix is completely crippled. I don't
even know why.

The biggest reason for UA has historically been because
IE was created to be incompatible with Netscape. And each
version of IE is incompatible with the last. There are a
lot of minor things. For example, a border line around a
table might be 1 pixel higher in one version than the other.
Or a DIV can be made to be a block element in one browser
but not in another. My own webpages all use redundant
DIVs and TABLEs for that reason. Older versions of IE can't
be made to set a DIV as a block element. It's only used as
a style marker. So if I want x to be on top of y then I have
to use a table. There are loads of little details like that. It
gets so complicated that many major websites use so-called
spaghetti code:

If it's IE6 then do X, else if it's IE7 then do y, else if it's IE 8
then do z, else if it's IE9 then do a, else if it's IE9 then do b.

Opera used to be at the other extreme. They were such
sticklers for official rules that their browser broke on many
websites. Web design is as much an art as a science. The
Opera fanatics wanted it to be pure science.

Over the years, Apple and Mozilla worked to
meet official standards. Opera is now just another wrapper
for Apple's webkit -- as is pretty much everything except
for Mozilla's browsers. 15 years ago, with IE and ActiveX,
Microsoft was king. Many sites only worked in IE. But gradually
that's changed. ActiveX was phased out. Flash is being phased
out. IE got left behind for being too quirky and unstable. It's
also notoriously unsafe. So Microsoft decided to try playing
fair and see if that would work. They've gradually changed their
browser to meet standards. But last I heard, they're still not
doing it. Nevertheless, they apparently hoped that with Win10
and Edge they'd have a chance at getting their monopoly back.
Here's a typical Edge UA:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like
Gecko) Chrome/64.0.3282.140 Safari/537.36 Edge/18.17763

Notice that it pretends to be everything else. MS have
asked webmasters to please pretend Edge is like Chrome
and FF. But they do still put "Edge" in the UA. Since Edge is
essentially a boutique browser, only available on Win10 and
reportedly not compatible, I block it by checking the UA for
"Edge".
Interestingly, IE11 has two modes. One is apparently like
Edge. But if you add a domain to a compatibility list in IE11
it will render in "quirks mode", which means it renders like
IE6. When you do that, IE11 switches from an IE11 UA and
sends the IE7 UA.

So Microsoft are one of the loudest voices saying webmasters
shouldn't use the UA, but that's all just a scam. They use it,
exploit it, spoof it, and depend on it themselves.

For people using a browser, the UA can be very useful.
Many sites will act up with just a slightly older version of
FF. (I'm using FF 52, which is 15 versions old. But it's
actually only 1 year old!) In most cases there isn't actually
any reason to demand a new browser. The webmasters
just can't be bothered to keep track so they demand
whatever is new. For both privacy and compatibility you
can solve a lot of problems by pretending to be using a
very typical, recent browser. That's why I'm travelling
as FF64 on Win7 rather than FF52 on XP. By September,
when Mozilla is up to version 217, I'll update my UA to
something tasteful and unremarkable, like v. 212.

But you need to be reasonable. If you pretend Windows is
Mac or pretend IE is FF then you're likely to cause problems
for yourself. If you spoof the UA it needs to be a compatible
spoof.