On desktops, the right side panel has a new item, navigation links. The first link is to the M4A1 design documents. These are the blueprints for the M4A1. As far as I can tell, they are a complete package.
These do not include tooling or how to documents, they are just the blueprints.
These prints are to pretty modern standards, but easy enough to read.
One fun thing I noticed was that they will often call out positions based on changing datum. A common datum is to consider the center of the front takedown pin to be 0,0. They do seem to use that as a starting point, but the trigger, selector and auto-seer holes are relative to the hammer pin hole.
This is because the relationship between those holes is critical, while their placement relative to the take-down bin is not.
For those on small screens, where the right-hand column is missing, scroll to the bottom of the page, you will find the link there.