$ git clone -n https://src.fedoraproject.org/rpms/rust-serde.git /var/lib/mock/f42-build-3528125-46296/root/chroot_tmpdir/scmroot/rust-serde
Cloning into '/var/lib/mock/f42-build-3528125-46296/root/chroot_tmpdir/scmroot/rust-serde'...
$ git fetch origin 63fb3b11f905671b284edbd99ed01cc09c6de498:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-serde
 * [new ref]         63fb3b11f905671b284edbd99ed01cc09c6de498 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 63fb3b1 Update to version 1.0.219; Fixes RHBZ#2351000