My only understanding of "ashcan" is "copyright loophole", and... this don't feel like that at all.

A solo journaling game of spies and coded messages · By
Hi! Yeah, that copyright loophole is where the term originates from, but for the Zine crowd its become almost a synonym of "prototype". An edition of a game that's made "quick and dirty" just to get it out there and have people playing it before (potentially) moving on to a version with fine-tuned rules, better art etc.