Proposal related to Content Handling UI in mozilla.dev.apps.firefox
Not all build in feed and microsummary types are included in the picture
Uninstall/delete button is grayed out for build in types
Every item on the list will start with one of these followed by a colon (Sorted in this order):
All microformats will be grayed out if "Enable smart elements" is unchecked
Drop down box should have content like this (+ icons):
Please excuse my lack of graphics skills and mixing of XP/Vista
Microformats does not have a name in the UI
Drop down box can hold many different types of apps: