$ git clone -n https://src.fedoraproject.org/rpms/ghc-regexpr.git /var/lib/mock/f41-build-side-1-2955633-35550/root/chroot_tmpdir/scmroot/ghc-regexpr
Cloning into '/var/lib/mock/f41-build-side-1-2955633-35550/root/chroot_tmpdir/scmroot/ghc-regexpr'...
$ git fetch origin 3d23049f433fad11d6084e58a950cde9dea46ac4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-regexpr
 * [new ref]         3d23049f433fad11d6084e58a950cde9dea46ac4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3d23049 retire: FTBFS, no longer needed nor maintained since 2011