$ git clone -n https://src.fedoraproject.org/rpms/rust-iri-string.git /var/lib/mock/f42-build-59177430-6571499/root/chroot_tmpdir/scmroot/rust-iri-string
Cloning into '/var/lib/mock/f42-build-59177430-6571499/root/chroot_tmpdir/scmroot/rust-iri-string'...
$ git fetch origin 610ca8f8c50d189af3a6b4d1a3c36ff620163c4b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-iri-string
 * [new ref]         610ca8f8c50d189af3a6b4d1a3c36ff620163c4b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 610ca8f Update to version 0.7.8; Fixes RHBZ#2353495