Methodology
W3C WAI materials inform the principles discussed here. Each article has a matching brief, a specific document example, and a human revision exercise. Source links are listed on article pages.
Paragraph Measure has two modes. Pixel-width mode counts the lines that this browser actually renders in a Georgia preview at the selected size and width. Character-cap mode wraps words at a selected character count. It reports average and longest displayed line length and total paragraph characters. Neither mode checks a real document's full accessibility, meaning, contrast, or reading context.
Named human editorial review is still pending. The current site is a review build, not an approved production publication.
For context, see W3C WAI visual presentation, text spacing, and reflow.