Android application package named ATV Desktop, version 0.1.9 Pro, labelled as a Chinese language build, 3.09 MB. It appears to be a launcher or home screen replacement intended for Android TV boxes, though the name gives no further detail about supported devices. An APK is installed by sideloading, usually after enabling unknown sources or using adb install. Scan it before installing, keep the original launcher available as a fallback, and expect the interface text to be in Chinese rather than English.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @tv_software. Enginerys does not host this file.