Android based smartphones from vendors such as Ulefone and Krüger&Matz contain "com.pri.factorytest" application preloaded onto devices during manufacturing process.
The application "com.pri.factorytest" (version name: 1.0, version code: 1) exposes a ”com.pri.factorytest.emmc.FactoryResetService“ service allowing any application to perform a factory reset of the device.
Application update did not increment the APK version. Instead, it was bundled in OS builds released later than December 2024 (Ulefone) and April 2025 (Krüger&Matz).