841-88X: Holdings, Location, Alternate Graphics, Etc. Fields
Definitions:
Extraction - finding the value inside the catalogued instance and copying it as is.
Example: a book may be written in English and yet may not contain the word “English” at all, so defining the book’s language would be generation rather than extraction
Example: An abstract could both be generated or extracted, the latter is possible for a scientific articles which often contain abstracts
Generation - producing the value which might not be found inside the catalogued instance
Evaluation - measuring qualities of the value, which is either generated/extracted or existing or obtained with some other tools