$ git clone -n https://src.fedoraproject.org/rpms/rubygem-rubygems-mirror.git /var/lib/mock/f40-build-1527448-23924/root/chroot_tmpdir/scmroot/rubygem-rubygems-mirror
Cloning into '/var/lib/mock/f40-build-1527448-23924/root/chroot_tmpdir/scmroot/rubygem-rubygems-mirror'...
$ git fetch origin 2af5a490d7948abb8ec48e069278803f22129e9f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-rubygems-mirror
 * [new ref]         2af5a490d7948abb8ec48e069278803f22129e9f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2af5a49 Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild