$ git clone -n https://src.fedoraproject.org/rpms/rust-libcramjam.git /var/lib/mock/f40-build-781176-131440/root/chroot_tmpdir/scmroot/rust-libcramjam
Cloning into '/var/lib/mock/f40-build-781176-131440/root/chroot_tmpdir/scmroot/rust-libcramjam'...
$ git fetch origin 77cfecd25e3c88530489003169b68eb1dc05fb88:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-libcramjam
 * [new ref]         77cfecd25e3c88530489003169b68eb1dc05fb88 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 77cfecd Update to 0.2.0 (close RHBZ#2262481)