wtf is miyoo-handheld-overlays?

Miyoo Handheld Overlays is a collection of image overlays for retro gaming handhelds running Onion OS, such as the Miyoo Mini. An overlay is a graphic that sits on top of the emulated game screen inside RetroArch, the emulator front end these devices use, and this project's overlays are built to make classic low resolution games look like they are shown on a screen with matching pixel density instead of being stretched flat across a much sharper modern display. The goal is not a perfect recreation of old hardware, but a subtle visual trick that suggests larger, warmer pixels instead of harsh, jagged ones. Color handhelds like the Game Boy get a soft pixel grid overlay, while monochrome LCD systems get a different grid meant to suggest the gaps between LCD crystals. The project author was careful to avoid heavier effects like lens shadows or rounded corners, keeping the focus on pixel structure so the Miyoo Mini's bright screen still looks good. The repository includes separate overlay presets and RetroArch settings for many systems, including Game Boy, Game Boy Color, Game Boy Advance, Game Gear, Lynx, WonderSwan, Neo Geo Pocket, Supervision, Mega Duck, Pokemon Mini, and Nintendo DS, plus game specific presets for a couple of titles. Each system's section in the README documents the exact Quick Menu settings needed, such as turning on the overlay, choosing the right preset, and adjusting scaling and image interpolation. To install it, you copy the RetroArch and Emu folders from the repository onto your SD card, merging them with your existing Onion OS setup, then configure each game or system's overlay through RetroArch's Quick Menu and save the settings as an override. Because the overlays are plain PNG files for RetroArch, they may also work on other handhelds with a similar 640x480 screen, though users would need to adapt the setup steps for their specific device. This project is aimed at owners of Miyoo Mini and similar retro handhelds who want a more nostalgic looking picture without heavy visual clutter. The README does not state a license.