Can I hide my extension's icon by default?

Question

My Chrome extension doesn't need an icon - it's a one-liner extension that doesn't want to take up space on your extension bar.

How can I hide the icon by default?

Answer 1

Due to a change spearheaded by Google, all extensions now must have an icon in the toolbar area or the "overflow" in the menu.

Even if you don't have a browser_action, your extension will display an icon (or failing that, a tile with extension name's first letter). If you do not declare a browser_action, it will be greyed out and non-interactive, but will still be there.

The idea of this change is to provide visibility of otherwise potentially stealthy extensions ("Hey user, did you even know you have those installed?"). It's, let's put it, debatable whether it's the best approach, but that was Google's decision.

Answer 2

To suppress this behavior, add "converted_from_user_script": true to the extension's manifest.json. This works as of Chrome 61.

It used to be that visiting a link to a user script (ending in .user.js) caused Chrome to package up the user script as a content script extension with a generated manifest which included the converted_from_user_script key. Of course, this no longer works because all extensions (except in developer mode) now have to come from the Chrome Web Store.