Access-Control-Allow-Headers - Response HTTP Header

I’m trying to find out a bit more information the Access-Control-Allow-Headers Http Hdr. Can you explain the origin, request options that are part of this header. Wanting to know how these work on requests and what advantages these have for me to use.

Below is the Header that is always returned from my requests:
Access-Control-Allow-Headers: origin, application-id, application-type, content-type, secret-key, request, user-token

Here are a few helpful links (the first one has great examples which explain the nature of the headers):

Thanks much for the info.