Here is what I quickly found on google:
Double Rainbow
Sometimes a second, larger rainbow can be seen above the primary arch. It is due to a second reflection of the sun's rays inside the raindrops. Its angle is approximately 52 °.
As the light is reflected twice, the colors are inverted from a primary rainbow, and it is also paler and therefore less visible. In theory, we could also see an infinite number of rainbows, resulting from the multiple reflections in the drop of water. In the laboratory, we were able to count 19!
Can I pass you the pictures if anyone is interested?