Thanks Tim for coming up with that great idea.
My favorite feature is the Oracle APEX Metadata Repository.
As you are probably aware of, APEX applications aren’t compiled. They are stored as metadata in a relational data model. Of course we aren’t allowed to access the tables in the APEX schema directly (e.g. APEX_050000), but APEX provides a bunch of dictionary views to read everything you want to know.
You can find all views mentioned in the APEX application builder:
The possibilities of those views are endless. You can simply get an overview of applications in your database. You can create your own reports on APEX activity log data. Write some QA checks, e.g. is every item named after it’s corresponding DB column.