It is used by goma recipe module and it is currently deployed via adhoc CIPD invocation code.
Instead it should be deployed on per-task level and available via PATH using more centralized and managable mechanism:
* On LUCI via swarming_task_template.json
* On Buildbot via cipd_bootstrap_v2.py
See issue 770990 for more info why.
Comment 1 by yyanagisawa@chromium.org
, Oct 3 2017