$ git clone -n https://src.fedoraproject.org/rpms/ghc-call-stack.git /var/lib/mock/f38-build-side-42-init-devel-595794-26162/root/chroot_tmpdir/scmroot/ghc-call-stack
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-595794-26162/root/chroot_tmpdir/scmroot/ghc-call-stack'...
$ git fetch origin b84c45048877741833ff959a110cdf9ae4b288e5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-call-stack
 * [new ref]         b84c45048877741833ff959a110cdf9ae4b288e5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b84c450 Convert to %autorelease and %autochangelog