Extensions, or add-ons, can modify and enhance the capability of a browser. Extensions for Firefox are built using the WebExtensions API cross-browser technology.
An extension adds features and functions to a browser. You create one using familiar web-based technologies: HTML, CSS, and JavaScript. An extension can use the same web APIs as JavaScript on a web page, but it also has access to an extra set of JavaScript APIs.
Jules is your end-to-end agentic product development platform. It reads your entire product context to figure out what to build next, comes up with solutions, and then ships a PR.