As a subscriber (content receiver), this application stores your:
Sign in token, on Android this will be your email address, on iOS this will be your firebase ID or email if (Sign in with email) permitted.
The streams you are registered to.
Messages sent to you.
As a stream provider (content publisher), this application stores your:
Email address, phone number (if entered).
The streams you have provided.
Messages sent from you.
When using this service as a content publisher this application stores your email and an encrypted login token.