The optional features in the JSON parser allow it be configured to almost be a fully-compatible parser for JSON5.

There's just a few missing features, documented here:
https://stackoverflow.com/questions/68312227/can-the-jackson-parser-be-used-to-parse-json5

Summarised as:

• hexadecimal numbers
• trailing decimal points on numbers (added via Add option to accept non-standard trailing decimal point (JsonReadFeature.ALLOW_TRAILING_DECIMAL_POINT_FOR_NUMBERS) #773)
• plus signs before numbers (added via Add a feature to allow leading plus sign (JsonReadFeature.ALLOW_LEADING_PLUS_SIGN_FOR_NUMBERS) #774)
• extra whitespace characters

I propose that additional Jackson features be added for each of these JSON5 features to allow Jackson to be used as a fully-compliant JSON5 parser.

(#612 was a similar but more specific request, though it seems that feature is already covered)

EDIT: Following work has been done:

• Add option to accept non-standard trailing decimal point (JsonReadFeature.ALLOW_TRAILING_DECIMAL_POINT_FOR_NUMBERS) #773 adds JsonReadFeature.ALLOW_LEADING_DECIMAL_POINT_FOR_NUMBERS to allow trailing decimal points on numbers
• Add a feature to allow leading plus sign (JsonReadFeature.ALLOW_LEADING_PLUS_SIGN_FOR_NUMBERS) #774: adds JsonReadFeature.ALLOW_LEADING_PLUS_SIGN_FOR_NUMBERS to allow leading plus sign on numbers