This repository contains the Perl 6 design documents, also called "Synopses", in Pod (5 and 6) format. A regularly updated HTML version is available.
Historically, these documents have determined the direction of Perl 6. As implementations matured, this role shifted (and still shifts) towards documenting the experience from the implementations.
Instead the test suite is becoming the specification, and the "specs" in the repository name of the design documents tends to mean "speculations" now.