To build Dooble 2.x on your GNU/Linux system with Qt 5.9 and Git, follow these steps: Clone the Dooble Repository: Open a terminal and run the following command to clone the Dooble repository from GitHub: "bash git clone https://github.com/textbrowser/dooble.git" Navigate to the Dooble Directory: Change into the Dooble directory: "bash cd dooble" Install Required Dependencies: Ensure you have the necessary dependencies installed. You can install them using your package manager. Common dependencies...