$ git clone -n https://src.fedoraproject.org/rpms/media-downloader.git /var/lib/mock/f42-build-side-1-3501732-45976/root/chroot_tmpdir/scmroot/media-downloader
Cloning into '/var/lib/mock/f42-build-side-1-3501732-45976/root/chroot_tmpdir/scmroot/media-downloader'...
$ git fetch origin f65b5c2ceebcfd06c5d9c65443cb29aa0bdaed4c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/media-downloader
 * [new ref]         f65b5c2ceebcfd06c5d9c65443cb29aa0bdaed4c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f65b5c2 Update to 5.3.2