websites should be banned from knowing the operating system they're running under. no exceptions. the web development industry has collectively lost their privilege to know what os im using. i will continue taking away standard web features until you agree to fire the imbeciles that put "linux isn't supported! you're doing scary things that may not work!" messages on my fucking textbook reader. whatever your terrible pdf.js clone is doing that requires knowledge of my operating system, stop doing it immediately
but platform-specific browser bugs need to get found somehow
then ask the user their operating system, dickhead. also you're not clever enough to tell the difference between an intermittent issue and a platform-specific browser bug, you don't get to play that card
but users are stupid and in-band detection is easier
i don't care! learn to talk to people who don't know computers! greater harm is done to me personally by your shitty fucking os detection warning messages than will be done to you if you are forced to sit down for two seconds and direct an elderly user to open system preferences and take a picture of the "about" section