$ git clone -n https://src.fedoraproject.org/rpms/git.git /var/lib/mock/f40-build-2086157-50111/root/chroot_tmpdir/scmroot/git
Cloning into '/var/lib/mock/f40-build-2086157-50111/root/chroot_tmpdir/scmroot/git'...
$ git fetch origin a8ab7b524dc420913420c2d4fbe7afbdcd2a7925:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/git
 * [new ref]         a8ab7b524dc420913420c2d4fbe7afbdcd2a7925 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a8ab7b5 Disable t6300.35 t6300.107 t6300.108