https://www.techspot.com/news/93443-version-100-chrome-edge-firefox-may-break-websites.html
This is the heads and tails of loosely typed languages
QuoteSlack is optimized for Firefox version 520. The version number of the userAgent is extracted as a string, not an integer.
I remember this both elated me and drove me nuts when I started using PHP. Prior that that I had mostly used strongly-typed languages. Strings are strings and integers are integers. They don't magically transform back and forth based on context. In PHP they do... but it depends on the context. Sometimes they don't.
So type juggling becomes less predictable and tends to lead to logic errors, rather than syntax errors. Syntax errors are great. Make one and the program fails to compile or, for an interpreted language, run. So you treat a string as an integer in C and it's game over. No compile. No run. No strange behaviors in the final product. On the other hand, it's tedious. PHP gets rid of all that tedium, but then sometimes you end up with results that take days and months and years to manifest and hours and days to track down.
If you want the specifics on why I posted the above, read this
https://miketaylr.com/posts/2021/03/firefox-version-520-works-in-slack.html
It's the kind of thing all programmers will look at and say, "Are those people nuts," but they'll say it in private because they know they've done things just like this ;-)
Well if they hadn't gotten into an idiotic race to higher version numbers for incremental changes and updates...