$ git clone -n https://src.fedoraproject.org/rpms/c4core.git /var/lib/mock/f40-build-2649678-66855/root/chroot_tmpdir/scmroot/c4core
Cloning into '/var/lib/mock/f40-build-2649678-66855/root/chroot_tmpdir/scmroot/c4core'...
$ git fetch origin 4d13b78a40f6a3336c53935aa282d9766dbb503a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/c4core
 * [new ref]         4d13b78a40f6a3336c53935aa282d9766dbb503a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4d13b78 Rebuilt with fast_float 6.1.0