Hey @Luc-Mcgrady, I have a question.
In the code base above the add_special_fields function there is a comment that states:

/// Add special fields if they don't clobber note fields.
/// The fields supported here must coincide with SPECIAL_FIELDS in
/// notetype/mod.rs, apart from FrontSide which is handled by Python.

To me that reads that any field added to the add_special_fields function also needs to be in SPECIAL_FIELDS.
You didn't add "CardID" to SPECIAL_FIELDS. Is that intentional? If so, why?

Well spotted! Seems like an oversight to me. I'll try and add a test for the future.

I can also add it. Though writing the test will take me a bit longer than you.

Too late 😅

No problem, thanks for the fix!