I too found this after reading about it here. I contacted them and received the following reply.
> Exposure notifications cannot be enabled without user consent, so if you have not turned MassNotify on, then it is not active on your phone. However, a recent Google update, which makes MassNotify available as an option in your phone's settings, is causing some users to see MassNotify in their app list. Apologies if this caused any confusion.
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> The appearance of MassNotify in the app list does not mean that MassNotify is enabled on your phone. The presence of the app merely means that MassNotify has been made available as an option in your phone's settings if you wish to enable it. For more information about this, please see this help center article from Google: https://support.google.com/android/answer/10775533
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> You can see whether MassNotify is active by going to Settings -> Google -> COVID-19 Exposure Notifications. The “Use Exposure Notifications” toggle at the top of the page will show you whether MassNotify is active or not. From this screen, you can also enable or disable MassNotify at any time.
> Exposure notifications cannot be enabled without user consent, so if you have not turned MassNotify on, then it is not active on your phone. However, a recent Google update, which makes MassNotify available as an option in your phone's settings, is causing some users to see MassNotify in their app list. Apologies if this caused any confusion.
>
> The appearance of MassNotify in the app list does not mean that MassNotify is enabled on your phone. The presence of the app merely means that MassNotify has been made available as an option in your phone's settings if you wish to enable it. For more information about this, please see this help center article from Google: https://support.google.com/android/answer/10775533
>
> You can see whether MassNotify is active by going to Settings -> Google -> COVID-19 Exposure Notifications. The “Use Exposure Notifications” toggle at the top of the page will show you whether MassNotify is active or not. From this screen, you can also enable or disable MassNotify at any time.