It would be possible to make zutils to support virtually any compressor, similarly to tar -I (-I, --use-compress-program=PROG), by using ini-style config where it would be defined what de/compressor to use for specific extensions. Even signature check would be possible, and internal/external support would define whether to use internal (for compressors supported internally already) of external support. It would also allow users to use other - non system, likely better, versions of de/compressors if they pleased.
I found very simple and effective ini parser ( github.com github.com/benhoyt/inih ), if you wanted to check. It seems to do this one thing well and still remain very simple. I attached sample config to the post. I know it would be revolutionary but would solve the requests to support this and that compressor, that are made every now and then. There would be no need to code all droves of new, fancy compressors as users could it themselves.
zutils-1.ini
Description: Binary data
