Still open source, still Apache 2. They're applying this EULA to "Some builds of stable ownCloud Infinite Scale releases provided by ownCloud GmbH" which is something you can do with any Apache 2-licensed software.
No. Software with a EULA like this is not free or open-source software. It violates freedom 0 of the fundamental software freedoms (FSF terminology) and the 'no discrimination against fields of endeavor' clause of the Open-Source Definition (OSI terminology).
Putting a restrictive EULA on a permissively licensed open-source project makes it non-free just like incorporating proprietary code.
You're not looking closely enough. There's no EULA on the project. There's a EULA on a specific set of binaries that are QA'd, bundled and distributed by a specific distributor associated with the project.
The project itself remains open source. You can `git clone` that source and use it under the apache 2 license, which is both free and open.
Furthermore, the development is still open, and there is still no CLA required to contribute.
Ok. So OwnCloud Infinite Scale customers are not using open-source software but a proprietary product closely related to some open-source code. Just like users of VS Code, Google Chrome, macOS, most distributions of Android, IntelliJ IDEA, GitLab, etc. And like other OwnCloud Enterprise customers.
