Much like #UbuntuTouch was picked up by the community under the alias UBPorts, it looks like #FirefoxOS was picked up by the community under the alias B2GOS.
B2GOS doesn’t appear to be maintained, but the build scripts are there. It also looks like a private company forked the code further and calls it #KaiOS (used on some Nokia smart/feature phones).
#UBPorts
- @Ubports
- https://ubports.com/