Please make sure to test your changes in a personal fork, before merging. It is imperative that travis tests pass before merging changes back, since broken travis tests implies that b2g bumper will break in production.
If you create a new branch in b2g-manifest, it is critical that you update
run_travis_tests.sh so that it invokes b2g bumper using the correct
mozharness config file(s) for your new branch. See comments in
run_travis_tests.sh for more details.