If Microsoft, who seem to be on an open source binge, would let loose WindowsPhone 8.1 ...
(It's not like MS are doing anything in that space anymore, except piling up Win10 stuttering on the remains ... and it might, perhaps, possibly, stub someone's toe ...)
If anyone has grafted a Metro Design scion on a Linux rootstock, that would be worth a look too.
But what about apps? That's a major part of the reasons why Windows Phone died, developers refused to commit resources to port/develop apps to yet another mobile platform.
IIRC, Palm webOS tried to fix that by allowing developers use familiar HTML/JS-based tooling (Enyo) [0] to build apps for that platform, but the die had been cast with iOS and Android.
I still have an old phone on which I'd installed CyanogenMod. Unfortunately, it's old enough that LineageOS isn't an option, the only updates were nightlies, and it never got past KitKat. About the only use case I can find for it now is as a SIP handset for my Asterisk box. I might just chuck it into a recycling bin, since it's a 3G handset to begin with.
There's an unofficial LineageOS build for my daily driver, but that, too, is trouble waiting to happen since VoLTE isn't supported, and I visit Michigan often enough to need it; I'm on T-Mobile, and a lot of their rural Michigan coverage is Band 12 LTE-only.
Cyanogen Inc, the company founded to do commercial work on it and running a lot of the project infrastructure, ran out of money after some weird things like cancelling a licensing deal with OnePlus suddenly and closed. community part of the project rebranded to LineageOS
Right. The community part - which is still alive and well in its rebranded form as LineageOS - was doing the most important work anyway (or, even if that's a loaded statement, the community part was extremely productive and still is).
> after some weird things like cancelling a licensing deal with OnePlus suddenly
just to be specific, they licensed the exclusive right to the cyanogen name in india to micromax (while previously licensing the non-exclusive right to oneplus in all regions), who then got an injunction against oneplus selling their devices in india.