The knx binding follows the dpt translators of the underlying calimero libraries. Calimero started to treat the 8 bit enumeration as strings to represent the allowed values and translates them from/to the knx bus accordingly.
So if, e.g. you want to send the value 0 to the knx bus for the DPT 20.105, you have to link the thing channel to a string item and send the value Auto.
The other mappings can be found in the calimero translator code:
The strings follow the official knx DPT specification. So, if you have a copy of that document, just take the values from there.
Please have in mind that the values can contain blanks like Building Protection, which is the correct value for DPT 20.102, value 4.