What is Debian’s Testing branch?

The Testing branch of Debian is a development branch in the Debian distribution, also known as “Testing” or “Debian Testing”. In Debian’s software development process, packages first enter the Unstable branch (also known as Sid), and after a period of testing and stability improvements, they are moved to the Testing branch. Packages in the Testing branch are generally more stable than those in the Unstable branch, but may still contain some bugs. The Testing branch is a continuously updated branch, with new packages and updates regularly added until the next Debian stable release. The purpose of the Testing branch is to allow users to use relatively stable packages while also experiencing the latest software and features.