What the Heck Is premium grain free feed UK?

https://horse-feed-products893.evergrovio.com/posts/horse-feed-for-chaff-and-cubes-a-practical-guide

Gentle horse feed for sensitive stomachs, designed to support digestive comfort, hindgut health and efficient nutrient uptake. A low-starch high-fibre formula with natural components to help maintain calm digestion and overall health.