["python","pipenv"]
What is pipenv [dev-packages] section for?

I'm learning pipenv and there's something I don't quite understand. Apparently your Pipfile can contain two sections: [packages] ... [dev-packages] .... As I understand it, the packages section is where the packages that you install are listed. But what is the dev-packages section for? How is it different from the packages section?
This section is for development requirements. So stuff like linters, unit test libraries, etc. All that is not needed on the user's machine. To install a package as dev-requirement add -d to install command (i.e. pipenv install -d ...), to install the dev-requirements section add -d to sync command (i.e. pipenv sync -d ...).