$ git clone -n https://src.fedoraproject.org/rpms/rust-iri-string.git /var/lib/mock/f41-build-side-1-3098684-39333/root/chroot_tmpdir/scmroot/rust-iri-string
Cloning into '/var/lib/mock/f41-build-side-1-3098684-39333/root/chroot_tmpdir/scmroot/rust-iri-string'...
$ git fetch origin 3707c6416685ddc0ef41c9d14ea4b97810bd35e1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-iri-string
 * [new ref]         3707c6416685ddc0ef41c9d14ea4b97810bd35e1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3707c64 Update to version 0.7.7; Fixes RHBZ#2318103