$ git clone -n https://src.fedoraproject.org/rpms/ghc-gitrev.git /var/lib/mock/f38-build-side-42-init-devel-813563-28316/root/chroot_tmpdir/scmroot/ghc-gitrev
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-813563-28316/root/chroot_tmpdir/scmroot/ghc-gitrev'...
$ git fetch origin 29edb2dcfee52474f600d5570af5038d27a1a4b0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-gitrev
 * [new ref]         29edb2dcfee52474f600d5570af5038d27a1a4b0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 29edb2d Convert to %autorelease and %autochangelog