$ git clone -n https://src.fedoraproject.org/rpms/rubygem-generator_spec.git /var/lib/mock/f40-build-2143356-50854/root/chroot_tmpdir/scmroot/rubygem-generator_spec
Cloning into '/var/lib/mock/f40-build-2143356-50854/root/chroot_tmpdir/scmroot/rubygem-generator_spec'...
$ git fetch origin 23bfcc036d108394f3687910142e27ce1c454127:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-generator_spec
 * [new ref]         23bfcc036d108394f3687910142e27ce1c454127 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 23bfcc0 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild