We have lots of requests to .well-known/apple-app-site-association (AASA) because we use Universal Link in our app. In my understanding the file is downloaded once on app install (and on update).
We have every day about 75.000 requests to AASA regardless of traffic on our site. Our traffic and our app install vary a lot. Our app installs are from 80 units up to 1000 units per day. But on each day we still have approximately 75.000 request to AASA.
Only few request (about 500) are going to the root folder instead of .well-known. So the fallback mechanism can not be the reason for so many requests.
All these requests are logged with a UserAgent like
swcd (unknown version) CFNetwork/894 Darwin/17.4.0
Only version numbers vary. Just very few requests per day are from other user-agents.
We do not use any Cache-control header at the moment as big companies doesn't do it either (for example Facebooks AASA). I think Cache-control header doesn't help as each app only loads the AASA once in my understanding.
What is the reason for this high and steady number of requests to AASA?