Web Sources logic is to locate first release id (album) in ParserScriptIndex an then to parse Album info in parserScriptAlbum step.
Source (.Src) files posted in mp3tag forums use different approaches of parsing album info: HTML and XML.
Wondering why not to use always XML since it is much better formatted then HTML. On top of that HTML is not stable (discogs might modify HTML tags construct in release pages at any time making ParserScriptAlbum unstable/unusable).
Ideally the usage of XML in both ParserScriptIndex and ParserScriptAlbum but combined with appropriate customizing would make it really powerful.
E.g. search by Artist and album. First, search only by artist (API artist search) and then filter (XML) results with given album title. Filtering can be extended with all possible fields (Year, Format, Genre, etc). A kind of Filtering popup similar to current .src popup but dedicating a label and a field for each possible tag would be needed in this case.
I know the interface between Filtering popup and Parser script is difficult but I believe that might be feasible.
Customizing would be needed to let user chose which fields should be extracted from ALBUM release. Scripting code would take into account the flag from customizing and then include/exclude the tag from process.
Less script files would be needed by this approach.