See example failure:

https://ci.chromium.org/p/chromium/builders/luci.chromium.try/linux_angle_rel_ng/140

Traceback (most recent call last):
  File "/b/swarming/w/ir/kitchen-checkout/recipe_engine/recipe_engine/run.py", line 287, in _new_run
    recipe_result = recipe_script.run(api, self.properties, self.environ)
  File "/b/swarming/w/ir/kitchen-checkout/recipe_engine/recipe_engine/loader.py", line 98, in run
    self.run_steps, properties, environ, self.PROPERTIES, api=api)
  File "/b/swarming/w/ir/kitchen-checkout/recipe_engine/recipe_engine/loader.py", line 626, in invoke_with_properties
    arg_names, **additional_args)
  File "/b/swarming/w/ir/kitchen-checkout/recipe_engine/recipe_engine/loader.py", line 589, in _invoke_with_properties
    return callable_obj(*props, **additional_args)
  File "/b/swarming/w/ir/.cipd/pkgs/11/bc0c53121227803f6e39ff54eff89c469b8eaf55/build/scripts/slave/recipes/chromium_trybot.py", line 45, in RunSteps
    return api.chromium_tests.trybot_steps()
  File "/b/swarming/w/ir/kitchen-checkout/recipe_engine/recipe_engine/recipe_api.py", line 750, in _inner
    return func(*a, **kw)
  File "/b/swarming/w/ir/.cipd/pkgs/11/bc0c53121227803f6e39ff54eff89c469b8eaf55/build/scripts/slave/recipe_modules/chromium_tests/api.py", line 873, in trybot_steps
    disable_deapply_patch) = self._trybot_steps_internal()
  File "/b/swarming/w/ir/kitchen-checkout/recipe_engine/recipe_engine/recipe_api.py", line 750, in _inner
    return func(*a, **kw)
  File "/b/swarming/w/ir/.cipd/pkgs/11/bc0c53121227803f6e39ff54eff89c469b8eaf55/build/scripts/slave/recipe_modules/chromium_tests/api.py", line 888, in _trybot_steps_internal
    mastername, buildername)
AssertionError: No bot config for master/builder [tryserver.chromium.angle / linux_angle_rel_ng]

Currently the ANGLE CQ is blocked, so could use some Trooper assistance with this. Have a speculative CL up here but unsure if this is the right approach:

https://chromium-review.googlesource.com/c/angle/angle/+/968542