$ git clone -n https://src.fedoraproject.org/rpms/R-jpeg.git /var/lib/mock/f39-build-1535861-36251/root/chroot_tmpdir/scmroot/R-jpeg
Cloning into '/var/lib/mock/f39-build-1535861-36251/root/chroot_tmpdir/scmroot/R-jpeg'...
$ git fetch origin 4df4bb829388b3123259a40124a1da4129cd7996:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-jpeg
 * [new ref]         4df4bb829388b3123259a40124a1da4129cd7996 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4df4bb8 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild