When you use the git clone command on your Ubuntu machine, you are actually using a pre-installed version of Git that is bundled with your operating system. This means that you do not need to install Git separately in order to use it.

Ubuntu, like many other Linux distributions, comes with a package manager that allows you to install and manage software packages on your system. Git is one of the many packages that is included in the Ubuntu repository, which is a collection of software packages that are officially supported by Ubuntu.

When you run the git clone command on your Ubuntu machine, the command is able to locate the pre-installed version of Git on your system and use it to download a copy of the specified Git repository to your local machine. This is because the git command is part of the system's PATH environment variable, which allows you to execute it from the command line without specifying the full path to the executable file.

If you want to check whether Git is installed on your Ubuntu machine, you can open a terminal window and type git --version. If Git is installed, the command will display the version of Git that is currently installed on your system. If Git is not installed, you will see an error message indicating that the command is not recognized.