I've moved my Internet Archive Metadata plugin for Picard out into its own repo and updated it to work with Picard v3 alpha 3. Probably limited enough in functionality that it's not useful to anyone but me (since the metadata on IA is pretty freeform and it likely only really works with the specific tracks I wrote it to help sort), but if you want to load Internet Archive meta.xml files as metadata in Picard, this may be a good starting place:
