Ever been in the middle of writing an E-lisp function and wanted a list of functions for working with buffers in Emacs? Or maybe you were meaning to juggle cons pairs for fun and wanted a list of functions to help you do so? Yea, me too, and I always reached for the internet for these needs, but my friend told me about M-x shortdoc today, so I am telling you.
Actually, I'll let describe-function tell it:
shortdoc is an alias for ‘shortdoc-display-group’ in ‘shortdoc.el’. (shortdoc GROUP &optional FUNCTION SAME-WINDOW) Pop to a buffer with short documentation summary for functions in GROUP. If FUNCTION is non-nil, place point on the entry for FUNCTION (if any). If SAME-WINDOW, don’t pop to a new window.
In short(doc): It's a built in cheat-sheet.