VTxx refers to V.R. Technology's "NES-on-a-chip" Famiclones, some of which having greatly extended capabilities. These capabilities are described in separate articles: VT01 STN Palette VT02+ PRG-ROM Bankswitching VT02+ Video Modes VT02+ CHR Pattern Data Layout VT02+ CHR-ROM Bankswitching VT02+ MMC3...| NESdev Wiki
In the west, the Nintendo Entertainment System exposed its graphics bus over the cartridge slot, allowing for all sorts of mayhem. But what you might also kn...| nicole.express