Editor

The list on the left holds Installed toolbars and Uninstalled drafts. Drafts autosave on this computer and stay separate from the installed revision until you install them. Editing a bundled toolbar makes a local override of it; Reset to Original removes the override.

• Install Toolbar, or Save and Apply for one already installed, installs the draft. It requires the revision the editor loaded: if another editor installed a newer one, the Editor shows both and offers Keep Draft on Latest Revision.
• Roll Back restores the previous installed revision. Duplicate, Export Source and Delete Local Toolbar do what they say.
• Edit site rules changes the toolbar's @match lines.
• Preview on Page runs the draft on the page you choose, in its current document, until you choose Stop Preview, close the Dashboard or navigate. Previews need Allow User Scripts too.
• Check for Update, for an imported toolbar, fetches its source URL again. Disjoint edits merge into a proposed draft; overlapping ones keep your version and show the upstream changes. A proposal changes only the editable draft: Use This Draft or Discard Proposal.

Runtime errors from the toolbar appear above the source, as they do on the toolbar.

Create with Gemini describes a new toolbar or refines the open draft, with Gemini Nano on this computer. The model receives an API reference, an example, your request and the current draft, never page content. Its revision opens as a diff for review. Generation never installs or runs code, has a 120-second deadline, and can be cancelled with Cancel Generation. Output with syntax or metadata errors gets one repair attempt and otherwise stays editable with its diagnostics.