When drawing a DFD I will often group things logically on the diagram, different local file datastores might be together as are external services out of scope, various AWS services etc. Currently the diagram is draw with things in random places. Using a Boundary would accomplish this but in some cases there isn't a boundary.

I was thinking it may be useful to have a logical group similar to a B

We need to add some text in the readme that says that examples in this repo are not examples of good systems, but rather contains bad insecure systems that are easy to model.

Same goes with the threat models examples, most of them will actually be ok, but models should be used as examples and tailed to the particular needs of the viewer context and reality.

(maybe put this as DISCLAIMER.