This file is in the Public Domain, and the author waives all legal rights to it. This protocol contains features core to the way the tabbed desktop environment (TabbDE) functions. This shouldn't be used by any applications, it's a core part of the finished DE. Only one application may register itself as a fallback handler, and the WM should expect this to happen at early boot. The fallback interface exists so that the DE can ask the user for what to do when encountering an unknown scheme or MIME type. Each event corresponds to some missing mapping. The fallback handler should prompt the user for input or otherwise find a handler for the given mapping, update the config files, and then send back a resolve event. If, for whatever reason, this is impossible, the fallback handler should send back a reject event.