0003 Content format 1

• Status: accepted (2026-10-29)

Decision

• One <astl-doc format="1" lang> root; optional <astl-page id label> wrappers (first-class pages: titles, per-page check, page restore). label, not title, because title is the HTML tooltip attribute.
• Structured data uses child elements (<astl-option>, <astl-alt>) instead of JSON in attributes: options can hold rich text, lang spans and math, and the format is easy for people and language models to write.
• lang is required: it drives grading (decimal comma, diacritics, case rules) and screen reader pronunciation.
• Every format carries a version: format on the document, v on elements, format in keys and snapshots.

Consequences

Sources stay readable HTML that any WYSIWYG can produce; views are deterministic and cacheable by hash.