[lanstin]

Most important thing to convey is the conceptual framework used and assumptions made to simplify things. e.g. "We will fix problems only by altering the base image, not the build system." "We will not change to 64-bit build as a part of this change." The sort of thing so that if someone really internalizes the perspective, they will be able to decide all the details on their own. Also a basic picture is always very popular. The details should be in git someway or another, but being able to use the details quickly is the job of the overview. I find it useful to document common change workflows ('To add another type of processor, add the class name to this map in this file, provide a jar implementing that class here, and add a new ID to the enum here.')