> How does the Bose app talk to the device?

what options can there possibly be? it uses bluetooth.

> Wireshark can probably be used to analyze it.

bluetooth has reasonable security built in. bose products make use of it.

I have, at [1], though this is literally the first time I dabble in android apps, so quality is alpha at best. I use it frequently ant works for me though.

[1] https://github.com/DavidVentura/Bose_QC35_Android

I don't mean "it's not a high tech native experience with dark mode". I mean the app works poorly, all the time, and gets in the way of actually using the headphones. For example: whenever my headphones are paired with both my phone and laptop (because the app allows for two devices to be paired at once??) I have to manually disable my laptop in the app to listen to phone audio, the "drag down to connect" interface rarely works properly, etc. It really is a very poor experience when compared to BT headphones that don't require an app to manage their state.