$ git clone -n https://src.fedoraproject.org/rpms/edk2.git /var/lib/mock/f39-build-2232951-53351/root/chroot_tmpdir/scmroot/edk2
Cloning into '/var/lib/mock/f39-build-2232951-53351/root/chroot_tmpdir/scmroot/edk2'...
$ git fetch origin bc6d394be4bf90f4a882fdd4d3dd8393be794f5c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/edk2
 * [new ref]         bc6d394be4bf90f4a882fdd4d3dd8393be794f5c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bc6d394 set PcdSetNxForStack = TRUE for strict nx builds