They will upstream stuff, but sadly they are not going to mainline.

https://mastodon.social/@GranPC/112690143171368646

No. It uses Hallium (Android kernel, basically).

It’s already delivered - a Mastodon user got one.

But getting an OEM to make a phone under your brand is easy. The real question is how long will they keep the software maintained?

These people seem like passionate Linux enthusiasts, so one can hope.

According to the Librem people: this is Android kernel (& other low level stuff) with Debian userspace, not a true Debian phone. https://social.librem.one/@dos/112686932765355105

Looks nice! Is this yours (OP)? If so, are you aware of Bavarder? It seems to have quite some features. (But it is unmaintained and broken right now so Alpaca is a welcome replacement.)