rcirc-url-regexp

rcirc-url-regexp is a variable defined in `rcirc.el'.
Its value is

"\\b\\(\\(www\\.\\|\\(s?https?\\|ftp\\|file\\|gopher\\|nntp\\|news\\|telnet\\|wais\\|mailto\\|info\\):\\)\\(//[-a-z0-9_.]+:[0-9]*\\)?\\(?:[-a-z0-9_=#$@~%&*+\\/[:word:]!?:;.,]+([-a-z0-9_=#$@~%&*+\\/[:word:]!?:;.,]+[-a-z0-9_=#$@~%&*+\\/[:word:]]*)[-a-z0-9_=#$@~%&*+\\/[:word:]]\\|[-a-z0-9_=#$@~%&*+\\/[:word:]!?:;.,]+[-a-z0-9_=#$@~%&*+\\/[:word:]]\\)\\)"

Documentation:
Regexp matching URLs. Set to nil to disable URL features in rcirc.