Moby Linux AMI - future and build source

As Docker for AWS is abandoned, are Moby Linux AMIs abandoned too?

Is the source for building the AMI available please?

Whilst we evaluate switching our hosting platform we have an urgent bug caused by the version of containerd in the 18.09.2 image (link below). That image is based on Alpine 3.5 and containerd wasn’t in the repos back then, so I’d like to see how it was installed to see if I can safely upgrade it to v1.2.3 with minimal container downtime.

Another option would be to jump to 19.03.0-ce-aws1 stable but that’s a much bigger jump with many more unknowns that might include configuration changes that break the config set up by the 18.09 CloudFormation template. It will upgrade docker so the whole swarm will have to come down and back up again.
Also there have been several docker engine releases since 19.03.0.