Fan control's internal data structures can be dumped at runtime using the fanctl dump command, which triggers fan control to write the structures to a /tmp/fan_control_dump.json file. That file is a normal JSON file that can be viewed, or the fanctl query_dump command can be used as a shortcut to just print portions of the file.
This page has additional information about the fanctl command.
The flight recorder contains interesting events such as each time the zone target changes.
It can be printed with:
fanctl query_dump -s flight_recorder
The object cache contains the most recent D-Bus properties of all of the groups from the groups.json files. If any of the D-Bus properties had a value of NaN (not a number), it is deleted from the cache so won't be present.
It can be printed with:
fanctl query_dump -s objects
One can restrict the output to specific names with -n and properties with -p:
The -n option will match on substrings.
Print the full entries of all temp sensors in the cache:
fanctl query_dump -s objects -n sensors/temperature
Print just the Value properties of all temperature sensors in the cache:
fanctl query_dump -s objects -n sensors/temperature -p Value
This allows one to do something like find all Functional property values that are false:
fanctl query_dump -s objects -p Functional | grep -B 1 false
The zone configuration contains values like the current target, current floor, and any outstanding floor or target holds.
It can be printed with:
fanctl query_dump -s zones
Parameters are key/value pairs set and used by actions.
They can be printed with:
fanctl query_dump -s parameters
Fan control maintains a map of objects paths of the group members to the services that own them.
It can be printed with:
fanctl query_dump -s services
Fan control can dump a list of all of its configured event names along with their group names.
It can be printed with:
fanctl query_dump -s events