$ git clone -n https://src.fedoraproject.org/rpms/gdb.git /var/lib/mock/f42-build-side-1-3533462-46361/root/chroot_tmpdir/scmroot/gdb
Cloning into '/var/lib/mock/f42-build-side-1-3533462-46361/root/chroot_tmpdir/scmroot/gdb'...
$ git fetch origin c9be69e4ce8af9d54ff68bceb5d928aeb9f9a893:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gdb
 * [new ref]         c9be69e4ce8af9d54ff68bceb5d928aeb9f9a893 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c9be69e Remove gdb-16.2.tar.xz from sources