I'm generally quite happy with Picard, but one thing that bothers me is that it sets Language:
eng even for works with the "instrumental" relationship attribute; typically I'd rather those use
zxx, and that difference may become important if I ever get around to creating a filter for non-lyric files. Is it for safety, where "instrumental" might mean more like "the main vocals have been removed, but not the backing" (along the lines of the "karaoke version of" relationship), or is it just a programming oversight? It's probably a trivial plugin to fix it, but I'm curious about any reasoning that may have gone into that.