Search ":wq" (github.com)

It's also interesting that if you limit the search to the C language, it looks like the search ignores the ":" after the first dozen or so hits and the remaining entries are matches for "wq" in variable names, etc. e.g.:

   extern struct workqueue_struct *kcrypto_wq;

Edit: Actually, this seems to be true of most languages...

"write file and quit"

It's the vim command to write & quit.