I wonder how much effort it would be to put together something expanding on this that's really friendly to new developers exploring a system. The goal would be to have something that looks more like a traditional swimlane diagram, but with human readable labelling of the connections. The open telemetry data should provide a nice skeleton and then maybe use some LLM summarisation (with access to the source code) to label what's going on.
There are local code <-> LLM interfaces though (CLI tools, editor extensions), and if you can figure out a suitable prompt you can get pretty similar experience. (Of course, you'll also want to run an LLM locally as well)
I love diagrams to represent how systems are setup and run. At one employer, they had hundreds of spreadsheets around the network drive which often linked together via formula or VBA code, along with queries out to databases.
I built a file parser (in VBA, because that is what was available) to log every file reference to a big table, the generate graphviz code to visualize it.
It's easy to say "tons of stuff uses $datasource", but it's way better if you can show exactly how much and the impact of changes.
It was incredibly useful when we changed our domain and all network drive mappings broke.
