The post popular answer includes: History of the browser user-agent string related discussions:
2022 (87 points, 20 comments) https://news.ycombinator.com/item?id=31246438
2019 (62 points, 22 comments) https://news.ycombinator.com/item?id=21085388
2018 (558 points, 168 comments) https://news.ycombinator.com/item?id=16525559
2013 (100 points, 32 comments) https://news.ycombinator.com/item?id=6674812
Also, I doubt tricking servers would indicate creating consumer confusion with the trademark.
ISTR that Netscape used to have in it's README or INSTALL (or maybe an "about"-like menu entry) a note that the name of the browser is pronounced Mozilla while only being spelled N-E-T-S-C-A-P-E.
I have been omitting it for decades with great results.
> Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Mobile Safari/537.36
It is Mozilla (nope), Linux (yes, in a sense), Android (yes) AppleWebKit (not Apple and not WebKit), KHTML (nope), Gecko (nope), Chrome (yes), Mobile (yes), Safari (nope).
So maybe they owe something to Mozilla, Apple and KDE.
[1]: https://www.pcworld.com/article/435584/why-windows-10-isnt-n...
(realistically though, the '9x' problem does make a lot of sense)
Now Apple has the year in the OS version we'll have people wondering in a few years what happened to iOS 19-25.
Opera/9.80 (X11; Linux zvav; U; en) Presto/2.12.423 Version/12.16
It did keep the version at 9.80, presumably because >=10 must have caused problems somewhere.
Blanking out the user agent would have to be pushed by either Apple, Google, or Microsoft. And out of those I feel like only Apple would do it. iCloud private relay doesn’t end up breaking websites since companies care about not degrading the experience for Apple users and make sure the site still works.
Even tor-browser doesn't dare to modify the user agent string in any major way. It's almost impossible to lie about because trackers don't actually care about your user agent. They're identifying your device/OS through side channels (canvas, webgl, fonts, etc).
why haven't we deprecated this junk
Because the reason it is the way it is in the first place is compatibility with sites that are doing things objectively wrong already, which makes it really hard to get them to change.
The problem is that poorly designed systems limit access or disable features based on a user-agent allowlist, which is never the right answer. There is no right way to do it because it's always wrong, but people choose to do it anyways.
I'm personally a fan of treating broken sites as broken, but I understand that realistically any "alternative" browser has to deal with all the broken sites designed for whatever came before it because otherwise most normal users won't consider switching.
If I were made King of the Internet for a day and able to enforce any changes I wanted on everyone, all the major browsers would have to change their user-agent string to something totally unique on the same day, intentionally breaking any sites that are doing it wrong for everyone so the broken sites are forced to fix their own nonsense. That'd come maybe two or three decrees down the line from "All ISPs are required to provide a globally routable IPv6 block in accordance with RFC 6177, providing only CGN IPv4 is a capital offense".
The main exception to this was Opera back when it had its own engine, which did use Opera at the start of its fairly clean default UA string. Then when they reached version 10 they had to make the primary version 9 with a second real version later in the string as sites couldn’t cope with two digit version numbers…
Opera in the late 90s / early 2000s was excellent. It was lightweight and snappy. Among the first to support tabs. The Presto engine was the most performant on machines of the era. The trialware/adware was annoying, but the browser was solid. The built-in email client was decent as well.
In 2009 they launched a very interesting web server / sharing feature with Opera Unite, which unfortunately didn't gain traction.
Opera Mini was the best mobile browser for a few years as well, before smartphones took off.
There's a field in the Volume Boot Record of disc volumes, in the PC compatible world, that was supposed to be the name of the OEM whose software formatted the volume. It was (and is) a few bytes of identifying human-readable text. Operating systems ended up doing string comparisons and parsing numbers, and breaking in odd ways, including not even recognizing their own handiwork, when operating system vendors did not use the name of the first vendor.
* https://jdebp.uk/FGA/volume-boot-block-oem-name-field.html
It has probably been long enough since MS-DOS 3.3 and in turn the Browser Wars that someone is right now failing to learn from history and making this mistake anew, yet again, somewhere.