Is Python Notebook Viewer safe?

Python Notebook Viewer executes JavaScript and HTML embedded in local .ipynb output cells.

When a local notebook file opens on file:// pages, the extension parses the notebook JSON and renders notebook-controlled rich outputs into the page. JavaScript, HTML, SVG, Markdown, headings, and raw cells are inserted as page content, so code embedded in notebook output can run in that local renderer.

Part of this rating comes from analysis signals we haven't published as detailed findings yet.