# Sandbox [Chrome Docs](https://developer.chrome.com/docs/extensions/mv3/manifest/sandbox/) :::tip Chromium Only Firefox does not support sandboxed pages. ::: ## Filenames - `entrypoints/sandbox.html` - `entrypoints/.sandbox.html` - `entrypoints/sandbox/index.html` - `entrypoints/.sandbox/index.html` ## Definition Plain old HTML file. ```html Title ```