A condition express the state of some part of the system, for instance if we are flying, if the system is armed or tumbled. A condition is a single bit and can thus only be true or false.
All conditions are collected in a bit field that expresses the full state of the system, or at least all the parts that are relevant to the supervisor.
All conditions can be found in the src/modules/interface/supervisor_state_machine.h file.
The condition bit field is used to trigger state transitions.