$ git clone -n https://src.fedoraproject.org/rpms/rubygem-narray.git /var/lib/mock/f42-build-865194-172845/root/chroot_tmpdir/scmroot/rubygem-narray
Cloning into '/var/lib/mock/f42-build-865194-172845/root/chroot_tmpdir/scmroot/rubygem-narray'...
$ git fetch origin 624561fe8e28423ebd45f54d249df1002e000444:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-narray
 * [new ref]         624561fe8e28423ebd45f54d249df1002e000444 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 624561f Rebuild for https://fedoraproject.org/wiki/Changes/Ruby_3.4