HTML workbench

The preview is off until you ask for it. When shown, the HTML renders inside a frame with no scripts, no same-origin, and no navigation, after DOMPurify stripped scripts, styles, and forms; data: image URIs survive sanitizing and render in the preview.

• No fetching. External scripts and styles are listed, never loaded. The preview is the exception: remote images that survive sanitizing ARE fetched by the frame; scripts, forms, and navigation stay blocked.
• No sanitizing claim on output: format and minify re-serialize the tree as-is; sanitizing happens only in the preview path.
• No CSS processing, the formatter touches markup whitespace, not stylesheets; pre, textarea, script, and style content stays byte-for-byte.
• HTML parsing is error-recovering. Malformed input is never rejected, it is normalized the way a browser would.