So, this year MDN Web Doc revamps there website designs and contents.
Here you can seeMDN Web Docs
Also find the Reference link at the bottom of this article.

Lets quickly go through what's new there:

1. Brand new logo. M monogram using underscore to convey the
   process of writing code.

2. Trending and favorite dark mode is added.

3. Completely new homepage with search in center and blog articles
   below that.

4. Soon, MDN will come up with MDN Plus. MDN Plus is subscription
   based module, which will include more content. As per MDN Docs,
   notifications, article collections and an offline experience
   might be the part of this plan.

Some important links:

1. HTML Documentation Index
2. Javascript
3. React from Web Doc
4. Angular from Web Docs
5. Vue from Web Docs
6. Git and Github Overview from Web Docs
7. Cross Browser Testing from Web Docs

And much more are there, Go and explore it.

Add the links in comment which you found to be new in MDN.

Cheers!!