CS50 Manual Pages is a web app at manual.cs50.io that simplifies (some of) the manual pages for the C standard library and C POSIX library for students less comfortable by providing explanations for (some) functions' synopses, descriptions, return values, and examples. It includes all of the functions in these header files but only simplifies those that students are likely to use in CS50 itself.
Underneath the hood, the web app uses pandoc to convert Linux's manual pages to HTML and regular expressions to modify them.