I was looking for this information as well. They have a donation page - https://www.signal.org/donate/ https://www.signal.org/donate/ - unlike the Mozilla Found

I was looking for this information as well. They have a donation page - https://www.signal.org/donate/ https://www.signal.org/donate/ - unlike the Mozilla Foundation/Firefox, so if enough people decide to use it, and to make regular(ish) donations, it could work. See Wikipedia.