$ git clone -n https://src.fedoraproject.org/rpms/mutt.git /var/lib/mock/f40-build-2200861-51793/root/chroot_tmpdir/scmroot/mutt
Cloning into '/var/lib/mock/f40-build-2200861-51793/root/chroot_tmpdir/scmroot/mutt'...
$ git fetch origin e3bef1eb9143708200b55b7bf8724663becf9340:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mutt
 * [new ref]         e3bef1eb9143708200b55b7bf8724663becf9340 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e3bef1e Fix C99 compatibility issue