It's been already 2 years I am using this daily and 2FA is here to stay so this extension will be maintained for at least the next 3 years. So far only one issue was created (when amazon give the code with spaces) and solved quickly (within a day).

The simplicity of it should make this extension low maintenance. The import/export is a guarantee for migration (helpful for me also to manually sync with android's Aegis Authenticator).