It causes a crash when used if not holding a blueprint.  That normal I assume?  Only noticed because the default keybind is also default for side inserters mod.  If so then feel free to delete my pointless report.
ERROR:
The mod Beautiful Bridge Railway caused a non-recoverable error.
Please report this error to the mod author.
Error while running event beautiful_bridge_railway::kap-bbr-cycle-key (ID 142)
Item is not blueprint.
stack traceback:
beautiful_bridge_railway/control.lua:19: in function <beautiful_bridge_railway/control.lua:15>
stack traceback:
    [C]: in function 'is_blueprint_setup'
beautiful_bridge_railway/control.lua:19: in function <beautiful_bridge_railway/control.lua:15>