As I newly came across this page (don’t speak Russian, but google translate does a good job on the page) I immediately would love to have it for the Original SailfishOS as well:
https://community.omprussia.ru/documentation/software_development/reference/public_api.html
Probably together with the python libs from here:
(I tried to document my personal first Steps and Hiccups with Sailfish App Development here, probably someone find it useful or someone from Jolla thinks some of the points could be worth to be considered for a Documentation Update. Thanks to all of the patient people from the IRC, which help out kindly https://cloud.10hoch-6.de/index.php/apps/cms_pico/pico/home/SailfishDevelopment#page-toc-1)