What is AWAF?
There isn't an agreed approach to structuring Salesforce Apex code and organising files and modules. Most orgs organically grow into a big ball of mud, where it's impossible to untangle anything without frustration. Other orgs early on adopt a framework like FFLIB (Apex Enterprise Patterns), created by Andrew Fawcett. And other orgs achieve some level of modularity with unlocked packages and internal libraries.
The goal of the Apex Well-Architected Framework (AWAF) is to propose a new way to structure an Apex codebase and to provide opinionated recommendations on what libraries and tools you should use.
It's not a "put this here" kind of framework. It's a set of ideas to help you and your team make better decisions as your org grows. It's based on the same concepts covered in Clean Apex Code—things like modularity, coupling, cohesion, and testability—but it doesn't force you into a specific setup.
Our vision is that every team can implement AWAF, yet each implementation can be completely different. In a way, no one should be able to tell you what an org using AWAF looks like; instead, they should be able to tell you what working in such an org feels like. A developer may work on two completely different codebases, yet the experience should feel the same.
Finally, AWAF is meant to be a modern alternative to FFLIB for those who find the framework unsatisfactory.