<include ref="ExampleLib.xml"/>
I should be able to name a library using the xml extension as long as a file with the aslx extension references it? Right?
Even if they have nothing to do with each other, this just makes sure the Quest creator can include it into it's referencing files?

Yes, sir.

You can't load an .xml from the GUI, though. That's the only difference I've found.

You cannot load library files of either sort into the GUI. I like to use .xml extensions for libraries because then I can set them to open in a text editor by default.

Hmm...

I prefer naming them .xml, too, but I can load library files through the GUI on my machine -- only .aslx files are displayed/selectable, though.

EDIT

Wait...

You probably meant loading them to edit them, now that I think about it.