How does it differ from https://weasyprint.org ?

WeasyPrint is great, but PlutoPrint takes a different angle: the engine is all C++, so it’s faster and lighter on memory. It can render directly to PNG as well as PDF, and has stronger SVG support.

PlutoBook looks very impressive. Is it based on another renderer?

Doesn't look like it:

> PlutoBook depends on the following external libraries:

> Required: cairo, freetype, harfbuzz, fontconfig, expat, icu

> Optional: curl, turbojpeg, webp (enable additional features)