I designed and wrote the API

Anyway, ascset is a command to allow a driver to accept 'options', of the developer's choice, in the driver code via the API.
So whatever 'options' they implement in the 'ascset' function that the API calls, is whatever is available.
The norm is also to accept "ascset|0,help" to return the list of ascset options available.
However, what they implement is up to them.
e.g. in my Gekko driver if you look at the code, it reports the list of options when you pass it 'help'
If Canaan wasn't violating the cgminer license like they are doing and hiding the source code, it would be the .set_device defined function in the driver code.
But again, it is possible, but not guaranteed, that 'help' may tell you what the options are - but you'd need to see the code to be sure what they do.
success: {'session': 1675108800, 'success': [{'ip': '10.138.23.226'}], 'error': [], 'results': [{'node': {'ip': '10.138.23.226'}, 'result': [{'result': "{'STATUS': [{'STATUS': 'I', 'When': 426204, 'Code': 118, 'Msg': 'ASC 0 set info: fan-spd|frequency|hashpower|led|pdelay|reboot|voltage|workmode', 'Description': 'cgminer 4.11.1'}], 'id': 1}"}], 'error': False}]}