within a container "emsdk install" raises "Cannot change ownership to uid 95607, gid 89939: Invalid argument"

As per the title says, the tar extraction keeps the ownership of the files, that at least in some versions is ver 65k
Probably I could workaround this with the uid and gid mapping mechanism, but 6k ids for a container is quite standard limit.

I suggest to do the tar extraction without preserving gid and uid

Specifically in line 517 of emsdk.py
returncode = run(['tar', '-xvf' if VERBOSE else '-xf', sdk_path(source_filename), '--strip', '1'], cwd=dest_dir)
add '--no-same-owner' as a parameter if on a linux platform