[xwlhexiv] Late formatting

When can data later in the source of a document affect formatting of data that was transmitted earlier, a lot earlier?

For HTML, tables can't be rendered until all rows are read and column widths known.

A long word could affect the margins of the entire document.

Of course, JavaScript manipulating DOM.

Such features make document rendering needlessly slow on low-power low-bandwidth devices, and are not needed most of the time, especially when the purpose of the document is its content and not its presentation.

Create a document format that eliminates slow features.  For a successor to HTML, this requires redesigning things from scratch.