Unknown Microsoft Login Appearing in Saved Passwords

Hi, I recently noticed an unknown Outlook/Microsoft account (oliveconscious13@outlook.com) saved in my Firefox logins. The email and password appear to be randomly generated, and the account’s preferred language is set to Russian. I have never seen or used this account before. Here are the key details: My Firefox account was created on June 8, 2025. The unknown Microsoft account was created on July 8, 2025. I only have two devices connected to my Firefox account: my Mac (where the account first appeared) and my Windows PC. The account is also showing up in Chrome’s saved passwords, which I never intentionally synced with Firefox. This is a brand-new Mac purchased directly from Apple, so I know it wasn’t a used device. I’m trying to figure out: How this account was added to my saved logins. Whether this was synced from another device. If there’s any security concern or if my account may be compromised. Could you check my sync history or logs to see which device added this login, and advise on how to make sure my saved logins are secure?