The standards speak!
The very recent STD 66 annex RFC 3986 states, in 1.1.3:
An individual scheme does not have to be classified as being just one
of "name" or "locator". Instances of URIs from any given scheme may
have the characteristics of names or locators or both, often
depending on the persistence and care in the assignment of
identifiers by the naming authority, rather than on any quality of
the scheme. Future specifications and related documentation should
use the general term "URI" rather than the more restrictive terms
"URL" and "URN" [RFC3305].
- my side-claim that a URI is either a URL or a URN is not true anymore
- my suggestion to change Policy URL to Policy URI is a must-do
- changing Keyserver URL to Keyserver URI comes highly recommended as well
Let's just do it as the standard states, change every URL to a URI.