There are still the design docs (<a href="http:&#x2F;&#x2F;design.perl6.org&#x2F;" rel="nofollow">http:&#x2F;&#x2F;design.perl6.org&#x2F;</a>) which are essentially spec documents. They are what implementors have been using over the years. Don&#x27;t forget the tests came from Pugs and now Rakudo is using the same test suite, so it&#x27;s more portable than you perhaps imagine. The tests are the stamp of approval for a version number conformance. If you can pass all the versioned tests then you are that version of the language. I think that&#x27;s a lot stronger statement than the engineers <i>think</i> they understood a spec document, even if formally specified. What are your thoughts on why that isn&#x27;t ok or worse than relying on pure docs?