2. ?
3. Chrome (or more specifically CEF -- Chromium Embedded Framework, the one used by Spotify et al.) is significantly more heavy than UL. Memory use is massive. Google doesn't care about API stability and ABI breakage is so common you'll have to keep up with all API changes (the ones published and documented anyway...) to get anything done. Good luck embedding Servo!
4. ARM support is coming.
---
> the others are 'community maintained'. Whatever that means.
I maintain the Rust binding to Ultralight [0] via the CAPI to provide an ergonomic way for people to work with it. Adam is busy improving Ultralight itself, so I find it worthwhile to maintain it. That's what it means.