Two things about that in reply to your comment: 1. Right now Firefox Monitor uses your Firefox account for signups. For somebody like me who already has a Fire

Two things about that in reply to your comment: 1. Right now Firefox Monitor uses your Firefox account for signups. For somebody like me who already has a Firefox account, I don't see a net difference in risk here. 2. If you don't want to make one, then Monitor is transparent in that they just use https://haveibeenpwned.com https://haveibeenpwned.com under the hood (source: https://support.mozilla.org/en-US/kb/firefox-monitor-faq#w_how-does-firefox-monitor-know-i-was-involved-in-these-breaches https://support.mozilla.org/en-US/kb/firefox-monitor-faq#w_h...), which doesn't require anything more than submitting your email and passing their Google captcha. It's unfortunate that they're not more forthcoming about this, but the option is there.