Here is a screenshot of how a library structure will look when you enable the Create archive option on an environment. All the files will be inside a build folder containing the build id number (BLxxxxxx). On the same level with the build folder, there will be a symlink pointing to the Launch library that is inside the build folder. All the custom code files will be inside the build folder. The hosted library files will also be inside the folder (like AppMeasurement.js for example).
For a library hosted on Akamai the things are a little different. When an extension is installed in the Launch catalog, the hosted lib files are stored on Akamai in a central location. Then each build will have the same files like you see in the above screenshot except that the hostedLibFiles folder is no longer there. The library will use the hosted lib files stored in the central location.
It will be different than it is in DTM. You can view it directly now if you configure an Environment for Archive, then publish a build to that environment and hit the download link. I will ask one of the developers to provide more details on what changes you'll see and the rationale for them.