$ git clone -n https://src.fedoraproject.org/rpms/rubygem-mechanize.git /var/lib/mock/f39-build-1499358-34744/root/chroot_tmpdir/scmroot/rubygem-mechanize
Cloning into '/var/lib/mock/f39-build-1499358-34744/root/chroot_tmpdir/scmroot/rubygem-mechanize'...
$ git fetch origin fc799a6879912bcc487e338eb04b353862ec904f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-mechanize
 * [new ref]         fc799a6879912bcc487e338eb04b353862ec904f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fc799a6 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild