btnx is a daemon that enables rerouting of mouse button events through uinput as keyboard and other mouse button combinations.
For example, you can configure an extra mouse button to send a Ctrl+Alt+Right command to switch workspaces. This is especially useful for mice with more buttons than Gnome or KDE can properly handle, or mice that need evdev and a 100 step howto to register button events at all.
btnx integrates revoco, a program that allows changing MX Revolution's wheel behavior.