COVID AND THE VACCINE - TRUTH, LIES, AND MISCONCEPTIONS REVEALED, page-3242

If you want my opinion, the delta variant is not a mutation. A virus that finds a new host gets two things. 1) a new place to reproduce and 2) a library full of new components that it can swap in to improve itself and adapt to its host. It seems likely to assume that the delta variant originated by swapping in a spike protein from another harmless human corona virus and now infects and behaves like the common cold.