Hello!
This is the Debug UI that Post-Processing FX uses to test effects in-game when you call ppfx_debug_show; Previously it was included in the PPFX folder, but because I used the same UI in my other libraries, maintaining a different version in each project was chaotic, so now you only need to import CyberUI if you need the debug UI, which is actually optional - it will not crash if you don't import it (this also makes the PPFX .yymps file less bloated).
This also means that you only need to import CyberUI package once, if you have my other libraries.