Child bridges bridge/bridges.json
Bridges of their own for some drivers, each paired in Home on its own with the main bridge's code. Moving a driver here (or back) makes its accessories new to Home: add them again and fix their automations.
Edit the JSON instead (for the settings the form doesn't show; it keeps them as they are).
Saving checks the file the way the helper will at its next start. A restart puts it to use.