File with a QM extension contains a compiled translation file – the source and target text in different language, stored in a binary format. Such format facilitates searching within the Qt application, during the translation process. Files are created with the Irelease command of the Qt project with a .PRO extension, a single QM file for every TS translation source file.

QM files are generated in the Qt Linguist software, used to create translations of graphic applications within Qt environment. This environment, originally developed by the Norwegian company Qt Development Frameworks, was later acquired by Nokia and currently supported by Digia company.