kevgski Thank you! It works for local libraries since I can get the path:
const libraries = require('sketch/dom').getLibraries();
const someLibrary = libraries;
const libDocPath = libraries.getDocument().path;
But if the library is a 'remote' library,
.path returns a RSS URL.
I find out that there would be a temp local URL for an added asset library, but how to get it?