The migration target. A page is a document; a table in that document is a block; a block is a folder with one JavaScript file and one CSS file, loaded on demand. Lighthouse scores of 100 are the design goal, not an achievement.
The author's work on it is groundwork: measuring what the AEM estate actually contains, cataloging its components against both platforms, and writing the platform-agnostic contracts (patterns, tokens, anatomy) that a block and an AEM component can each be realized from.