reminder: harden OS and detect platform version

[Thorin-Oakenpants]

currently OS is a slam dunk with widget fonts, and if RFP is off, math can back that up for math results we know, but it would be nice to some other fallbacks. There are bound to be things different in GV world vs desktop (feature detection etc)

lets focus on fonts (and we could probably apply this to any browser)

• https://arkenfox.github.io/TZP/tests/fontscripts.html
• I plan to add more test PoCs, such as by unicode version (going back to say v5.0) and analyzing that to see if we can get a small subset - i.e some code points from each release that indicate older platforms (e.g. windows)
• note we can already check for certain fonts per windows version (might get tricky with win11 except I think FF caps at win10 so it doesn't matter if we can't if we want to use this to detect/bypass a useragent lie) - abraham's speedy font face test

note: we don't have to be perfect with a result, as creepy said, the result can be like Win10

ToDo: build a platform-os test PoC page, e.g. like for Engine, Version. Hopefully this year

[Thorin-Oakenpants]

ps: Win7 TB doesn't support Braille, which is interesting: I need to update my VMs or ask AF users / Tor Project forum for help testing

[Thorin-Oakenpants]

arkenfox/user.js#1509 (comment)

So looks like my system font might not be 100% foolproof - awaiting results. This is me checking widget0 which is input type reset

see arkenfox/user.js#1509 (comment)

• different test but -moz-dialog, -moz-button, -moz-list, and -moz-field are still MS Shell Dlg \32

[Thorin-Oakenpants]

^ phew ... arkenfox/user.js#1509 (comment)

[Thorin-Oakenpants]

https://developer.mozilla.org/en-US/docs/Web/API

interesting things to look at: e.g. android vs desktop

• https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/capture#examples
• https://developer.mozilla.org/en-US/docs/Web/API/Barcode_Detection_API#browser_compatibility
• https://developer.mozilla.org/en-US/docs/Web/API/EyeDropper_API#browser_compatibility

[Thorin-Oakenpants]

https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/41347#note_2843379

just checking this entropy is already cpatured - font-optical-sizing and font-variation-settings should be listed under HTMLElementKeys right? I'm on win7 and my win10 VM is old - @abrahamjuliot

other than that

• not a foolproof way, since it's behind a pref, but a good example of OS version diffs
• comparing OS versions was something I've wanted to do for a long time and would have highlighted this

[abrahamjuliot]

Yeah, these should appear in computed styles. Nice detection. I wonder if there are more like this... found this -moz-osx-font-smoothing here.