[Klonoar]

It's likely referring to gyroscope, intended to guard against racks of devices sitting somewhere that don't physically move.

Humans move their devices even when typing.

[DaiPlusPlus]

iOS requires explicit permission to grant access to gyroscope info: I tried this page right now in Mobile Safari 16 and got a prompt:

https://sensor-js.xyz/demo.html

I think (though am uncertain) that it’s similar for App Store apps too.

[Klonoar]

I am aware, yes.

My assumption about an SDK like that is that it's getting that access through some assumed mean(s) that the user just clicks past without thinking.

[dns_snek]

Very interesting, on Android it's granted by default in both Firefox and Chrome.