confidence property
Confidence is the winning assertion's own confidence in 0,1, zero when its filer stated none. It is reported because it is a term of the rule that picked the winner, and it is the weakest term but one: it breaks a tie inside one rank and never lifts a weak source above a strong one.
Please note: This property should have been non-nullable! Since the specification file does not include a default value (using the "default:" property), however, the generated source code must fall back to having a nullable type. Consider adding a "default:" property in the specification file to hide this note.
Implementation
num? confidence;