HTML, CSS, JS knowledge base on browser standards support?

Question

css

1. Can you please tell me where you can watch the news on the developed and adopted standards JS, HTML, CSS?
   
2. Where you can see the support of certain elements of the standard for a specific browser and its specific version, all current browsers are of interest (that is, which version this or that tag works with, which version it works with and how this or that property is implemented, etc.) ?
   
3. Are there any tools to check the validity of the written code for a specific browser, indicating the version of this browser?
   
4. Where can I watch news about what's new in browser standards support?
   

Browsers of interest:
FF
IE
Edge
Safari
Chrome (as far as I understand all its clones have the same engine and will implement everything the same)
Thank you for your answers.

Answer 1

2 - https://caniuse.com/