Thanks for the review. To clarify: the extension doesn't request mail.proton.me access when you install it. The only install-time permission is contextMenus. The mail.proton.me permission is optional. Firefox prompts for it the first time you click the toolbar icon, and if you decline, the extension just opens a new tab each time.

It asks because of one feature: if Proton Mail is already open in a tab, the launcher switches to that tab instead of opening a duplicate tab. Firefox's tabs.query API requires host access for the URL being matched, so there's no way to detect an existing tab without it. The permission isn't used for anything else. There are no content scripts and no code that reads page content, and the full source is reviewable on GitHub (github.com/PyroDonkey/ProtonMail-Launcher).