$ git clone -n https://src.fedoraproject.org/rpms/ghc-haskell-src-exts.git /var/lib/mock/f40-build-1997971-44197/root/chroot_tmpdir/scmroot/ghc-haskell-src-exts
Cloning into '/var/lib/mock/f40-build-1997971-44197/root/chroot_tmpdir/scmroot/ghc-haskell-src-exts'...
$ git fetch origin 448d7a3e01edece54611486459fbb4ccfb34c90a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-haskell-src-exts
 * [new ref]         448d7a3e01edece54611486459fbb4ccfb34c90a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 448d7a3 bump release