Constant ELEMENTS 

pub const ELEMENTS: &[&str];

Every element name this vocabulary knows: HTML’s, and the SVG subset a chart is drawn with.

SVG names that carry a capital — linearGradient, foreignObject, clipPath — are absent because they cannot be written today: the ui module takes an element head to be all lowercase, so a camel-cased tag is read as a function call. Listing what cannot be expressed would make this table a wish.