To provide the core functionality of Mobilizon. Depending on this instance's policy you may only be able to interact with other people's content and post your own content if you are logged in.
This Service runs on a Mobilizon instance. This source code is licensed under an <a href="https://tldrlegal.com/license/gnu-affero-general-public-license-v3-(agpl-3.0)">AGPLv3 license</a> which means you are allowed to and even encouraged to take the source code, modify it and use it.