5.6 What does the testing directory contain?

Packages are installed into the `testing' directory after they have undergone some degree of testing in unstable.

They must be in sync on all architectures where they have been built and mustn't have dependencies that make them uninstallable; they also have to have fewer release-critical bugs than the versions currently in testing. This way, we hope that `testing' is always close to being a release candidate.

More information about the status of "testing" in general and the individual packages is available at https://www.debian.org/devel/testing