/** * Provides classes for identifying popular framework libraries. * * Each framework is identified by a subclass of `FrameworkLibrary`, * which is simply a tag identifying the library, such as `"jquery"`. * This represents the framework as an abstract concept. * * Subclasses of `FrameworkLibraryInstance` identify concrete instances * (or copies) of frameworks, that is, files (or scripts embedded in * HTML) containing the implementation of a particular version of * a framework library. * * Subclasses of `FrameworkLibraryReference` identify HTML `