While trawling around the WikEmacs site today, I came across this page on troubleshooting that explained some commands that I wasn’t familiar with. The first two are helpful if you are trying to search out library problems. For example, if you want to know where your version of org-mode is coming from you could find out with 【Meta+x】 locate library 【Return】 org 【Return】 and Emacs will tell you where it is loading the library from
Library is file ~/tools/org-mode/lisp/org.elc
The related command list-load-path-shadows will show you if your load-path variable is causing one version of a library to shadow another. For example, when I run it, it tells me that the version of org-mode that came with Emacs is shadowed by the newer version from my tools directory.
Finally, and perhaps most useful, is the find-library command. Suppose you want to look at the code for a library you are using (including the core libraries), let’s say key-chord.el. Merely type 【Meta+x】 find-library 【Return】 key-chord 【Return】 and Emacs will open a buffer in a new window with the code loaded in it. Very handy.