[Dungeon Fantasy] Area Knowledge: What does it do?

[Rasputin]

I'm trying to piece together what Area Knowledge does in GURPS Dungeon Fantasy.

Area Knowledge is on the Dungeon Delvers Cheat Sheet in Adventurers, p. 17, but no template has it. As such, Dungeons doesn't have any mention of it, and neither does the DFRPG. Sages, however, does mention scholars using Book-Learned Wisdom (Sages, p. 8) to get that skill, and even gives an example of a scholar picking up Area Knowledge (Ice Caverns), which sounds like some kind of dungeon, though there's no specified game benefit for it. Wilderness Adventures has many uses of the skill, many of which are substitutes for Navigation in the specified area. Both Caverntown and Cold Shard Mountain have NPCs with Area Knowledge for those locales, though only Caverntown specifies a use, namely to avoid getting lost (Caverntown, p. 25).

Aside from the wilderness uses, what does this skill do? I can gather the urban uses from the Basic Set (though, since Dungeon Fantasy defines society as, "[T]own, where we buy and sell stuff," knowing the names of civic leaders isn't all that important in RAW GURPS Dungeon Fantasy). The uses in a dungeon, however, are a mystery for me. Does it substitute for some skill in the dungeon (like Traps) if the delver has Area Knowledge at a higher level? Something else?