$ git clone -n https://src.fedoraproject.org/rpms/rust-zlib-rs.git /var/lib/mock/f42-build-side-1-3497629-45961/root/chroot_tmpdir/scmroot/rust-zlib-rs
Cloning into '/var/lib/mock/f42-build-side-1-3497629-45961/root/chroot_tmpdir/scmroot/rust-zlib-rs'...
$ git fetch origin 152c2e933b1d494a9c2398207e40d37320145e89:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-zlib-rs
 * [new ref]         152c2e933b1d494a9c2398207e40d37320145e89 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 152c2e9 Update to version 0.5.0; Fixes RHBZ#2356555