What does the package manager use to list and download packages?

For some reason when I want to install a package it doesn’t display anything. Does it use a special php module that needs to be activated on the host?

It uses cURL. If you don’t have that, Package Management wont work.

To extract the zips, it uses by default the ZipArchive PHP extension. Most hosts have this installed; however, some hosts have a buggy version of it installed, and so we’ve provided a setting that allows you to fallback to PCLZip, another extension - to switch to it, set the System Setting ’archive_with’ to Yes.