Google seems working on making it easy to switch accounts in Google Messages
What this could be is the Google account that you’re currently signed into Messages with. This indicator could allow you to easily switch to another account. So far, the feature is not active, and Android Authority was able to activate it when engaging in a group chat, but hasn’t been able to see it with one-on-one conversations.
This doesn’t however mean that the feature will be available only for group chats. It just means the feature is still in the works and has not been refined yet. Also, a new option for profile management under the account menu was discovered, and this could be connected to the “Sending as…” option.
Last year, Google Messages introduced a Profile discovery feature, which helps you interact with people who are not already in your contacts.
On top of that, Google Messages has been working on dual-SIM RCS support for a while now, but so far, not everyone seems to have access to it. It’s basically in active testing for some users. It could be possible that this “Sending as” option can be used if you have two separate profiles with each connected to a different phone number.
However, as you might imagine, it’s quite early to know what exactly this feature would do and how it will exactly work. For now, nothing is functional so it seems that whatever feature is in the works, it’s still in its early development stages.
I personally think that being able to easily switch your Google account in Google Messages would be a very useful feature. Especially if it’s connected to a dual SIM scenario.