This is because it's the default flag used in the recipes to dump a json output.
This CL also fixes some python3 lint issues in mb.py.
Bug: webrtc:13594
Change-Id: I9275b5da0963f801d3191703c2eb72d90befb5d7
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/248142
Reviewed-by: Christoffer Jansson <jansson@google.com>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Jeremy Leconte <jleconte@google.com>
Cr-Commit-Position: refs/heads/main@{#35986}
63472e5aea