Heimer is a desktop application for creating mind maps. It's written in Qt and targeted for Linux and Windows.
Here is a simple mind map of Heimer itself:
Heimer's source code is licensed under GNU GPLv3. See COPYING for the complete license text.
All image files, except where otherwise noted, are licensed under CC BY-SA 3.0: http://creativecommons.org/licenses/by-sa/3.0/
See https://github.com/juzzlin/Heimer/releases for available packages.
On Linux distributions that support universal Snap packages you can install Heimer like this:
$ snap install heimer
For more information, see https://snapcraft.io/heimer, https://docs.snapcraft.io/core/install
Please refer to the INSTALL document for build/install instructions if you're going to build Heimer from sources.
Building for Linux in a nutshell:
$ mkdir build && cd build
$ cmake ..
$ make
$ sudo make install