Where can I find a list of field IDs?
A list with the current fieldmap can be found in Additional information in the Fieldmap section
The IDs in the provided fieldmap are part of a "cleaned up" list. All other, not mentioned fields are not relevant for customers. These fields are for internal use only, their content is not fixed and therefore not guaranteed. In this respect, the interpretation of the field IDs should be limited to those officially documented.