I'm trying to use the API to get a list of all values in our custom udf_fields, but I can't figure out how to use it as it's not documented anywhere. I've tried guessing at a /api/v3/udf_fields endoint, and I think I'm on the right track as it's not telling me it's an invalid URL, it's instead telling me I haven't provided a module. 

Is there a way for me to get these values at all?