GPU Fan Meister does not support video cards by itself. This feature is added by plugins. Each plugin is a set of files that will be loaded by the main application.
Before you start using GPU Fan Meister, you need to install a plugin that supports your video card. You can download the required plugin from the Internet or write it yourself. Plugins should be placed in one of the search folders, in the subfolder plugins/<id>. For example, if the plugin is called amd-mesa-free and one of the search folders /usr/local/share/gpu-fan-meister, the plugin can be placed in /usr/local/share/gpu-fan-meister/plugins/amd-mesa-free to be detected by the application.
List of plugins supported by the GPU Fan Meister developer:
nvidia-nvml is a plugin for managing NVIDIA video cards that run under official proprietary drivers.
test-manual - a plugin that emulates the video card and allows you to manually set the current temperature.
Downloaded plugins will have the same access rights as the account from which GPU Fan Meister is launched, i.e. almost full access to all your data.
The first time you start the program, the "Enabled plugins" window will open, where you can select the plugins you want to automatically load at subsequent program launches. This window can also be opened manually - read more in this window description.