$ git clone -n https://src.fedoraproject.org/rpms/ghc-hxt.git /var/lib/mock/f40-build-2178162-51101/root/chroot_tmpdir/scmroot/ghc-hxt
Cloning into '/var/lib/mock/f40-build-2178162-51101/root/chroot_tmpdir/scmroot/ghc-hxt'...
$ git fetch origin b079b1c625963d237b1a4ca9f440390163441549:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-hxt
 * [new ref]         b079b1c625963d237b1a4ca9f440390163441549 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b079b1c bump release