$ git clone -n https://src.fedoraproject.org/rpms/ghc-torrent.git /var/lib/mock/f40-build-743558-111265/root/chroot_tmpdir/scmroot/ghc-torrent
Cloning into '/var/lib/mock/f40-build-743558-111265/root/chroot_tmpdir/scmroot/ghc-torrent'...
$ git fetch origin 72c7829c63e546153ba169eaeb9f43f8730d74ff:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-torrent
 * [new ref]         72c7829c63e546153ba169eaeb9f43f8730d74ff -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 72c7829 https://hackage.haskell.org/package/torrent-10000.1.3/changelog