Member mnx::FractionValue::FractionValue (NumType num, NumType den): Make this constructor constexpr when we drop C++17 support.
Member mnx::sequence::Event::MNX_OPTIONAL_CHILD (Rest, rest): orient
Member mnx::Sequence::MNX_OPTIONAL_PROPERTY_WITH_DEFAULT (int, staff, 1): orient property
Member mnx::sequence::NoteBase::MNX_OPTIONAL_PROPERTY (int, staff): perform
Member mnx::sequence::Tuplet::MNX_OPTIONAL_PROPERTY_WITH_DEFAULT (TupletDisplaySetting, showNumber, TupletDisplaySetting::Inner): orient
Member mnx::StaffGroupBarlineStyle: This appears to be a misnomer, and there is an outstanding issue 495 to clarify it. Currently mnxdom treats these as override options. Of particular concern is the instrument option, which adds useless complexity in the context of staff groups.