Haha yeah we have a tendency to merge a lot of "ready" work near the end.
We do plan to have a thorough rendering guide. We've just been putting it off as the renderer has been (and still is) in flux. Once the dust settles a bit we'll start investing in "documentation on-ramps".
Technical question: will there ever be a guide that talks through how the rendering part of bevy works? The graph and all is great, but really difiicult to get into without the help of discord.