Not sure if this is the best section to post this but, over time, I have upgraded my Bittle from having a NyBoard (fun!) to a BiBoard v0_1 (more memory, faster CPU, more fun!) to, recently, a BiBoard v0_2 with Hat Extension (with integrated voice module and Grove connectors, ultimate fun!). In this journey, I made the following diagram that mixes images already on the Petoi website to visually map the servo indexes with the board pin numbers. Perhaps others will find it useful.
I also used 6 mm P-Touch® labels, with the same info, affixed to the servo connectors. This made it easy to swap boards.
It's more clear!