A donation is gratuitous. It is not a payment for goods, work or services, creates no obligations between you and the developer, and grants you no rights, advantages or consideration in return: no access to any service, no support priority, no influence over the project's direction.
The software is and remains open and equally available to everyone — whether or not anyone supports it.
The developer provides no paid services — does not sell the software, access to it, its setup or maintenance, does not provide servers, and does not operate a communications service. You install and run the program yourself, on your own infrastructure and at your own responsibility.