From local experimentation, it seems that having a mode named "default" will still require me to explicitly pick the mode for pipeline execution.

$ dagster pipeline execute -m my_module -p my_pipeline

Pipeline my_pipeline has multiple modes (Available modes: ['default', 'test']) and you have attempted to execute it without specifying a mode. Set mode property on the PipelineRun object.

This diff was originally motivated by a Slack discussion during DogFoodDay Feb 2021, but I'm struggling to find it in Slack search. For now, I'll put this diff "on hold" until I (or someone else) can reproduce the advantages and convenience of using "default" instead of "dev".