$ git clone -n https://src.fedoraproject.org/rpms/rust-cargo_metadata0.15.git /var/lib/mock/f40-build-2189923-51418/root/chroot_tmpdir/scmroot/rust-cargo_metadata0.15
Cloning into '/var/lib/mock/f40-build-2189923-51418/root/chroot_tmpdir/scmroot/rust-cargo_metadata0.15'...
$ git fetch origin 2c0335df2d4676f5be5b0a22630a24859a7aedd3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-cargo_metadata0.15
 * [new ref]         2c0335df2d4676f5be5b0a22630a24859a7aedd3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2c0335d Initial import (cargo_metadata 0.15 compat package)