First-party presets that ship with the app (copied next to the executable as
shaders/).  They are original to this project and GPL-licensed with the rest of
the repository.

  vj-sharp-bilinear.slangp   crisp scaling at non-integer window sizes
  vj-scanlines.slangp        scanlines + optional RGB mask, with parameters

RetroArch's slang-shaders collection (CRT-Royale, CRT-Geom, ...) is NOT bundled:
its files carry many different licences.  Point Settings > Video > Preset folder
at a clone of https://github.com/libretro/slang-shaders to use them.
