There's a (large) middle ground between "personal project" and "official product". It not hard to imagine a project being build as a proof of concept as part of

There's a (large) middle ground between "personal project" and "official product". It not hard to imagine a project being build as a proof of concept as part of someones regular job, yet not making it to "product", much less "official" status (and never intended to), but still open sourced because it might benefit someone else.