https://www.techradar.com/news/the-a-to-z-of-photography-x-trans

Fujifilm’s X-Trans sensor takes a different approach to sensor design and particularly the way in which color is captured and processed. The company says this produces sharper detail with less false color and moiré effects in fine patterns and textures.

The secret of the X-Trans sensor design is its variation on the ‘color filter array’, the mosaic of red, green and blue filters which almost all digital cameras use to capture full color images. These are necessary because the individual photosites (pixels) on the sensor respond only to light intensity, not color. Without a color filter array, a sensor would capture only in black and white. What the color filter array does is to ‘force’ individual photosites to record only red, green or blue light, and the camera then combines and interpolates (‘demosaics’) this red, green and blue data to calculate a full color value for each pixel.