UX for internal property names is inconsistent

(Bug, Investigate , Priority: Medium, Test Status: No automated tests yet , Reported By Bad Link: Thing 3y284oe not found, )
UX
Summary: The problem here is clear, but the right solution is not -- this needs some careful UX thought.
Original email from Eric:
The editing UI for External Link Type shows Name and URL.

However, to access them, you use -> Name and -> _url. The latter is non-obvious from the UI; I expected (and tried) -> URL.

Very minor, but worth fixing someday.
The problem is the difference between the name and display name of the property. Both are being used correctly, but the inconsistency is confusing. Think about how to clarify this, possibly in both directions. (For instance, possibly display the name in small print if the display name is different; and possibly provide a more helpful warning if you give the Display Name for a Property without marking it as such.)