$ git clone -n https://src.fedoraproject.org/rpms/ghc-servant-client.git /var/lib/mock/f39-build-1713537-41228/root/chroot_tmpdir/scmroot/ghc-servant-client
Cloning into '/var/lib/mock/f39-build-1713537-41228/root/chroot_tmpdir/scmroot/ghc-servant-client'...
$ git fetch origin 8490f47166d8ccc344e3ffc4c8cd8f747d0fe4e4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-servant-client
 * [new ref]         8490f47166d8ccc344e3ffc4c8cd8f747d0fe4e4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8490f47 revised .cabal file