Quick Highlighter от AF88

Quick Highlighter lets you mark any selection on the current tab with your preferred color and clear it later with one tap. It requests only the activeTab and storage permissions, injects no remote code, avoids all inline scripts, and follows AMO policies for user privacy and security. Pick a highlight color in Options, click the popup to highlight your current selection, and remove highlights just as easily.

The extension is designed to be fast, private, and unobtrusive. It runs only when you use it and never collects or transmits data. Your color choice is saved locally using storage.sync so it can follow you across Firefox profiles that sync settings. The action popup provides two clearly labeled buttons: highlight the current selection and clear all highlights added by the extension on the page.

Under the hood, the background script injects a small, site-agnostic content script only after a user gesture. The content script wraps the selection in lightweight spans with a background color and a subtle radius. It uses safe DOM methods only and never writes innerHTML from untrusted sources. A built-in clear action unwraps those tags without touching the rest of the page DOM.