Member TagParser::MatroskaTagIds::icra (): Not sure what this is or should have been. Remove in v12.
Member TagParser::OggIterator::bytesRemaining (std::size_t atLeast) const: Remove this unused function in v11.
Member TagParser::OggIterator::readAll (char *buffer, std::size_t max): Remove this unused function in v11.
Member TagParser::OggPage::makeSegmentSizeDenotation (std::ostream &stream, std::uint32_t size): This function is unused and should be removed in v11.