@gdlg That’s great that you got things working for Arch with bloom! Maybe you could open a pull request to review your implementation and discuss potential changes to support the source URL you mention is a challenge.
It would be great to add support for Arch to the ros_buildfarm. Our policy is not to add new target distros to released rosdistros. But if this is working at the time we could consider turning it on when we start releasing for Lunar Loggerhead in a few months.
And in the mean time you should be able to test with a parallel deployment building Kinetic for Arch.