libmbim on CrOS is currently built from third_party/libmbim, which is a git repository tracking the upstream repository at https://cgit.freedesktop.org/libmbim/libmbim/. We initially set up a downstream repository to help streamline our development when we anticipated more frequent downstream changes. Having a downstream repository allowed us to shorten the turnaround time of landing changes on CrOS before those changes were accepted by upstream. Now that downstream development has slowed down and the delta between our downstream repository and upstream is essentially zero, we should migrate libmbim to the ebuild model to be more inline with other third-party packages.