Diagnostics are deliberately narrow
HTML parsers recover from many errors. A zero-diagnostic result only means this parser reported no tracked parse errors; it is not full conformance, accessibility, security, or rendering proof.
The parser runs locally with a 500 KiB input cap, 100,000-node and 100-level tree limits, and a 1 MiB output cap. It never fetches URLs, loads resources, uploads source, or saves a preset.