I excavate the entire web, hope that didn’t force things public before you had hoped. 
Congratulations on the Docs and joining the Pinegrow team.
Interesting and ironic though wouldn’t you think that “picture & srcset” should have been part of the list that they would have done themselves long ago? Especailly since its been prevalent to the standard of web development and responsive design, with each being virtually are as old as the Pinegrow app itself. ;—)
By comparison its harder to quantify how many potential 3rd party developers, looked and then decided to walk away over the many years that the Dev API Doc’s were not in place. A solid documented API is one of many factors that go into choosing whether a person wants to invest time into extending other peoples products. The same could be said regarding general documentation and its upkeep regarding users deciding to use products. So perhaps @RobM will be tasked to assist there also to update and build out the general docs?
Now that the API is officially being documented, your right @Marf I’m anxious to see what things the Pinegrow team will be able to accomplish now that this will no longer be a burden on the to-do list after so many years. ;—P