DevRel were often the ones writing and updating those docs, especially docs that are specifically tailored to integrating with specific frameworks or workflows.
Different developers have different styles. I'm personally inclined to seek out raw API docs, attempt to understand the mental model intended by the developer, then and figure out how to integrate that into my workflow myself. But I've learned from shipping a devtool that a lot of developers really appreciate tutorials that meet them at the libraries/frameworks they already use.
I always assumed docs were either written by the devs writing the software, or technical writers. My mental model of good documentation has two types: old-school, heavily technical (e.g. Postgres [0]), and friendlier-but-still-detailed (e.g. Django [1]).
The former definitely does not attempt to hold your hand in the slightest, whereas the latter has a Quick Start, Tutorials, and detailed information about specific components.
Different developers have different styles. I'm personally inclined to seek out raw API docs, attempt to understand the mental model intended by the developer, then and figure out how to integrate that into my workflow myself. But I've learned from shipping a devtool that a lot of developers really appreciate tutorials that meet them at the libraries/frameworks they already use.