What exactly is the Standard Assets Package?

When creating a new project I have the option to select the included asset packages. I can choose for example the 2D, Cameras or Characters package. But what exactly do these packages do? I can’t find any documentation about them.

I mean: the Cameras packages has something to do with the cameraviews, but what? Is it needed to have a camera in my project, or does it include some other things?

Thank you very much!

None of them are needed. They just contain various commonly-used premade scripts, shaders, effects etc. so that you don’t need to create your own. The names are pretty self-descriptive, but the best way to find out what’s in each is simply to try them.