RCB is the native file format used by Ripple Chat Bot. RCB files were used for storing custom chat commands and responses. The format is now obsolete.

RCB files were compatible with Battle.net. RCB files are no longer used as Ripple Chat Bot project has been discontinued. RCB files can be sometimes found on computers with older programs installed. Current version of Blizzard’s Battle.net doesn’t support Ripple Chat Bot client.