From Revolt Wiki

Hyalus is an end-to-end encrypted text and voice communication platform.

The developer has exhibited some weird behaviour deleting Git history, here[2] and here[3].

^ Dev response: "This was due to moving from one massive repo to multiple repos (hyalus-web, hyalus-desktop, etc) and not deleting history. All of the client source code (web, desktop, etc) is fully open-source and available on GitHub." -Asineth