@strypey GNUtoo doesn't post FUD.

It's the truth; https://f-droid.org/docs/Installing_the_Server_and_Repo_Tools/
"To build apps using F-Droid, Java and the whole Android SDK must be installed. This process is currently only developed on GNU/Linux, but we’d love patches getting it working on macOS and Windows. If you only want to make F-Droid repositories of APK files that you already have or don’t know what this means, then you can skip this section.

In order to build Android apps with the fdroidserver toolchain, Java, the Android SDK, and some other essential tools must be installed. Only parts of the Android SDK are available in Debian, so the Android SDK must be installed manually, as well as the packages that it requires (the Android SDK tools include some 32-bit binaries, so even 64-bit systems need these i386 library packages). The F-Droid tools use the Android SDK to build and inspect apps, so you must have the Android SDK installed and setup before using fdroidserver."

"The Android SDK is made available by Google under a proprietary license. Within that, the essential build tools, SDK platforms, support library and some other components are under the Apache license and source code is provided."