$ git clone -n https://src.fedoraproject.org/rpms/ffmpegthumbs.git /var/lib/mock/f40-build-2415254-60564/root/chroot_tmpdir/scmroot/ffmpegthumbs
Cloning into '/var/lib/mock/f40-build-2415254-60564/root/chroot_tmpdir/scmroot/ffmpegthumbs'...
$ git fetch origin 8a6c91f32b11905e078fff97c62eba2e42fcfb6d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ffmpegthumbs
 * [new ref]         8a6c91f32b11905e078fff97c62eba2e42fcfb6d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8a6c91f 24.01.95