What are the main sections of software packages in Debian?

The main software packages in Debian are divided into the following sections:

1. Main: Includes software packages that are free and comply with the Debian Free Software Guidelines.
2. contrib: software packages that adhere to the principles of free software but rely on non-free software or contain unpackaged source code.
3. Non-free: software packages that do not comply with the principles of free software, including proprietary software and other restricted software.

Each section includes a large number of software packages, which users can choose to install according to their needs. The main software packages are usually located in the main section, but sometimes it may be necessary to install packages from the contrib or non-free sections to meet specific requirements.