$ git clone -n https://src.fedoraproject.org/rpms/rust-proc-macro2.git /var/lib/mock/f45-build-44032-809/root/chroot_tmpdir/scmroot/rust-proc-macro2
Cloning into '/var/lib/mock/f45-build-44032-809/root/chroot_tmpdir/scmroot/rust-proc-macro2'...
$ git fetch origin f854783c5e573689d21f58f11888656e3cf79718:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-proc-macro2
 * [new ref]         f854783c5e573689d21f58f11888656e3cf79718 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f854783 Update to version 1.0.107; Fixes RHBZ#2502146