Effective November 1, 2023, Mozilla will be renaming Firefox Accounts to Mozilla Accounts. From Firefox accounts renamed Mozilla accounts - What you need to know:
A new account isn't needed and sign-in remains the same. Additional information is available in the referenced support document.
Why the renaming?
Over the years, Firefox accounts expanded its role beyond being solely an authentication solution for Firefox Sync. It now serves as Mozilla's main authentication and account management service for a wide range of products and services, supporting millions of active account customers globally. As such, the original "Firefox" branding no longer accurately reflects the broad scope of Mozilla's offerings. The renaming is intended to create a more consistent brand experience across all Mozilla surfaces, driving higher awareness of the portfolio of Mozilla products.
A new account isn't needed and sign-in remains the same. Additional information is available in the referenced support document.