Operating systems generally allow user override of locale settings, and browsers generally respect that; I use a locale which officially has 12 hour time as its standard (Australian English), and I always override it to 24 hour time in user preferences (although Australia is rather inconsistent, e.g. in Sydney, train services use 24 hour time; in Melbourne, the metro trains use 12 hour time but the regional services use 24 hour time)
Interesting, so you're saying that that OS-level time preference is available via JavaScript? I wasn't able to figure out how to query that in a little bit of trying, so I assumed there was no API for it.
If there actually is, I'm now even more upset at that log web UI.
For me, the first returns 24 hour time and the second returns 12 hour time. Because 12 hour time is default for my primary locale (en-AU), but I override it to 24 hour time in my macOS settings.
I know the same works on Windows, and I’m sure it works on Linux too, just the way you configure it is different for each OS.
