I have 2 small complaints:
- I sometimes read some dubious content on MDN. For instance [JavaScript frameworks and libraries]^1. I don't think these tutorials for 5 frameworks provide any value over the respective official tutorials. Even more so with outdated tutorials: the Svelte one is 5 years old, and there have been major changes since then. ^1: https://developer.mozilla.org/en-US/docs/Learn_web_developme...
- The quality of the webextension doc is low. A clear problem is that it's mostly for manifest v2, with a few incomplete pages mentioning a transition to v3 or the compatibility with Chrome. In practise, I started developing an webextension with this doc, then had to switch to Chrome's, though Firefox was my primary target.