$ git clone -n https://src.fedoraproject.org/rpms/libfastjson.git /var/lib/mock/f42-build-3273900-41313/root/chroot_tmpdir/scmroot/libfastjson
Cloning into '/var/lib/mock/f42-build-3273900-41313/root/chroot_tmpdir/scmroot/libfastjson'...
$ git fetch origin a8c000b14a6e5aae0143bea538ac1a8b6eff6ca1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libfastjson
 * [new ref]         a8c000b14a6e5aae0143bea538ac1a8b6eff6ca1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a8c000b Rebuilt for https://fedoraproject.org/wiki/Fedora_42_Mass_Rebuild