$ git clone -n https://src.fedoraproject.org/rpms/ghc-stm-chans.git /var/lib/mock/f39-build-1711534-41228/root/chroot_tmpdir/scmroot/ghc-stm-chans
Cloning into '/var/lib/mock/f39-build-1711534-41228/root/chroot_tmpdir/scmroot/ghc-stm-chans'...
$ git fetch origin 42fd03e3ef313fa942e1766c627d9c904a20b264:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-stm-chans
 * [new ref]         42fd03e3ef313fa942e1766c627d9c904a20b264 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 42fd03e https://hackage.haskell.org/package/stm-chans-3.0.0.9/changelog