Android application package for Erge Duoduo TV version 1.2.3.0, a children's songs app for smart TVs and TV boxes; the name marks it as an unlimited build. At 9.42 MB the APK is not a schematic or firmware dump but software that is sideloaded onto Android devices. Installing it requires allowing unknown sources on the target box. Modified builds can carry unwanted code, so scan the package before installation and avoid using it on devices that hold sensitive accounts or data.
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.