PHP Integrator indexes PHP code and performs static analysis. This information is stored in an index database and the command line can then be used to fetch information in JSON format to provide various functionalities, such as autocompletion, code navigation and tooltips.
This is something I'd rather have avoided, but as this code acts as a sort of payload for editor extensions and plugins that are usually written in another language, stripping the dependencies requires those plugins to install them again via composer. This in turn requests that the users of those plugins have composer installed as well, which increases the entry barrier for new users.
Currently the core package is used to power the php-integrator-* packages for the Atom editor. See also the list of projects.
