Are you using the Akamai hosting option for your Launch libraries? If the answer is yes, then this post is for you!
We have been working with Akamai to implement cache control headers on DTM and Launch libraries. This functionality is now in production for both Adobe and Akamai. This means that all production libraries hosted on Akamai will now have a cache request of 60 min included in the header. However, this still a request and is up to the browser to respect the request.
Previously, we were not setting the cache control request, so browsers would make their own caching decisions, which lead to unexpected results occasionally.
If you are using Launch, there may be action required to fully deploy this feature. Your production library will have a request of 60 min without any action on your part. However, development and staging libraries for Launch will need to have either "-development" or "-staging" in their filename. If they do not, their cache control will be set to 60 min instead of 0 (don't cache). To correct this, you'll need to delete and recreate those environments. The newly created libraries will include the required "-development" or "-staging" respectively.
You'll have to actually create a build before that URL will return a real file. When you create your environments, it's just an empty URL until you actually assign a library to that environment and create a build.