$ git clone -n https://src.fedoraproject.org/rpms/ruby-gnome2.git /var/lib/mock/f40-build-733929-105574/root/chroot_tmpdir/scmroot/ruby-gnome2
Cloning into '/var/lib/mock/f40-build-733929-105574/root/chroot_tmpdir/scmroot/ruby-gnome2'...
$ git fetch origin da44099ebd91d8b413be9871ccc506da016c54d1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ruby-gnome2
 * [new ref]         da44099ebd91d8b413be9871ccc506da016c54d1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at da44099 new patch style