Based on the feedback, there is a real need for this. Currently, all the extension material is scattered and very limited. There are various third-party blog posts focusing on different areas, and sometimes contradictory. The main motivation behind making this is to make the barrier for entry less prohibitive for new contributors. I would greatly appreciate your insights on how to seamlessly integrate this tutorial into the existing documentation (add it as its separate block or some other way). If there are areas where the current documentation suffices or if there are ways to enhance the overall structure, I am open to making adjustments.
I recently tried to add a documentation patch for procedural languages, specifically PL/pgSQL and PL/Python, which is part of the procedural language section within the broader tutorial. You can find the ongoing discussion on the patch here.