This repository is for the maintenance of the PNG specification, the second edition of which was jointly published in 2003 by W3C as a W3C Recommendation, and by ISO as an International Standard ISO/IEC 15948:2003 (E) with identical contents.
This repository is being used to work on an Editors Draft, and also for discussion and update of any technical changes or additions. A First Public Working Draft of the Third Edition of PNG was published in October 2022. (Changes from Second Edition)
The PNG Extensions specification is also here.