This is the web version of the Lazarus Packages Repository.
Online Package Manager (OPM) is the tool that automates the process of installing, upgrading and configuring Lazarus packages. The packages are stored in the main repository (this website) as zip files, along with a JSON file. The JSON contains all necessary information about the packages. On request the packages are downloaded/extracted/compiled/installed into the IDE. If available, it's also possible to update a previously installed package from the maintainer webpage.