Some references if helpful:

* Elmish (F#) repo - https://github.com/elmish/elmish

* The Elmish Book (... remarkably good) - https://zaid-ajaj.github.io/the-elmish-book/#/

* Fable compiler - https://fable.io/

The F# community is very friendly (sub-communities as well), and there are plenty of good opportunities to contribute OSS work across any skill level.

Phosphor isn't hiring right now, but we will begin a search for FE/interface engineers soon. oliver@phosphor.co for anyone interested.