$ git clone -n https://src.fedoraproject.org/rpms/aria2.git /var/lib/mock/f40-build-1990978-43447/root/chroot_tmpdir/scmroot/aria2
Cloning into '/var/lib/mock/f40-build-1990978-43447/root/chroot_tmpdir/scmroot/aria2'...
$ git fetch origin abb9f47ead9dbd31dce1416468498bb7e53db589:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/aria2
 * [new ref]         abb9f47ead9dbd31dce1416468498bb7e53db589 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at abb9f47 fix undefined behavior leading to crash (rhbz #2119478)