This page looks at dark frame pattern noise at ISO 100, including the individual color channels (ProPhotoRGB color space) with both 14-bit and 16-bit captures.
All cameras have noise in the near-black shadows. One way to assess what gremlins might pop up in real-world images is to look at a dark frame shot with the lens cap on, at a high shutter speed—essentially zero exposure and thus capturing pure noise.
An interesting difference is seen between 14-bit and 16-bit capture.
Includes RGB and its color channels and grayscale for both 14-bit and 16-bit.