[RossBencina]

The C++ (draft) standards are open source:

https://github.com/cplusplus/draft

Last time I looked I could not find an equivalent repository for the C standards.

[AlotOfReading]

There isn't one. They publish completed drafts on the working group website:

https://www.open-std.org/jtc1/sc22/wg14/www/wg14_document_lo...

[RossBencina]

.pdf unfortunately. The C++ sources that I linked to are machine readable .tex.