The audio separation backend uses Demucs v4, including the four-source htdemucs model. The project's code is published under the MIT License. Demucs estimates the vocal, drums, bass and other parts of a mix; it does not supply ownership rights to any recording a visitor uploads.
The display typeface is Syne, served locally under the SIL Open Font License 1.1. Its license text is also included with the site's font files.
Acapella Extractor is independent of those projects. Their names identify the software and font used; they do not imply endorsement. Questions about the site can be sent through the contact page.