Files with the .PRI extension contain a composition of settings, such as file layout and definitions specific to the supported platform. It is used in the qmake software, which is designed for building previously designed and created apps in Qt SDK – short for Software Development Kit.

The Qt SDK is a cross-platform application for programmers, often used for creating mobile apps. Initially, the Qt SDK was devised by Nokia – later on, the software was overtaken by Digia.