>>tobr+(OP)
One of my ideas is for application windows to have a button to flip to the internals of the application - see threads, connections, progress bars, concurrent loops, memory allocations, even stacks. This is what I call an encyclopedic desktop.
>>samsqu+wv4
The JVM more or less allow you to do that. Its debugging and profiling abilities are amazing. You can also do most of these things (and more) with the various tracing systems of the linux kernel. (edit: typo)
>>ta988+Cx4
One approach that I find interesting is to use Wasm because it was designed as a portable execution format for lots of language types. It has an amazing amount of flexibility for byte working and execution.
It is fairly trivial to see all of main memory and single step execution of a wasm program. If one runs wasm3 in wasm3, you can then trace the inner interpreter as well. Check out the section on trace visualization.