The main site is located here: molly.im
The first paragraphs on the donation page:
The goal is to build a secure messaging app with integrated support for Monero payments and a decentralized backend.
The application will be based on the Signal fork Molly.im (henceforth ‘Molly’) but with a privacy-focused backend that allows the user to sign up anonymously (without phone number), encrypt their local database with passphrase encryption, RAM shredding, and more.
Monero features will include the ability to set up a XMR wallet, send and receive funds, keep track of the balance, and review the history.
But there is no need to have it in the messenger. That just sounds like a stupid idea: make your payment system connected to the internet, addressable by name and make it parse and load all kinds of media. Mobile OS have per-app sandboxing so why not take advantage of it?