Best Documentation for APIs, Products and Standards?

Question

What do you consider to be some of the best examples of technical/product documentation on the Internet, and why?It could be for an API, a standard, a spec, a licence, a product, release notes for a new version, changelog, whatever :)

0x008 · Accepted Answer

- GNU AWK[1] is really amazing.- FFMPEG[2] is really horrible.[1] https://www.gnu.org/software/gawk/manual/html_node/index.htm...[2] https://ffmpeg.org/documentation.html

Best Documentation for APIs, Products and Standards?

What do you consider to be some of the best examples of technical/product documentation on the Internet, and why?
It could be for an API, a standard, a spec, a licence, a product, release notes for a new version, changelog, whatever :)

- GNU AWK[1] is really amazing.
- FFMPEG[2] is really horrible.
[1] https://www.gnu.org/software/gawk/manual/html_node/index.htm...
[2] https://ffmpeg.org/documentation.html