qrc[1] are the resource files for data related to user interfaces, and ui[2] is the extension that the Qt Designer generates, for Widget based projects. Note that the initial PR used `ui` as a name for `*.ui`, but this seems overly general. Instead, we use `qui` here instead. Closes #3141 [1]: https://doc.qt.io/qt-6/resources.html [2]: https://doc.qt.io/qt-6/uic.html