$ git clone -n https://src.fedoraproject.org/rpms/rubygem-msgpack.git /var/lib/mock/f41-build-851589-166013/root/chroot_tmpdir/scmroot/rubygem-msgpack
Cloning into '/var/lib/mock/f41-build-851589-166013/root/chroot_tmpdir/scmroot/rubygem-msgpack'...
$ git fetch origin ac4778fd4d9614b05ac25e826eed61ad7874d24c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-msgpack
 * [new ref]         ac4778fd4d9614b05ac25e826eed61ad7874d24c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ac4778f Rebuilt for https://fedoraproject.org/wiki/Changes/Ruby_3.3