Feature Request: View layers

Suppose we consider a Photoshop metaphor. In this image editor, an artist can create layers that stack on top of one another. They can turn them on/off on a side panel. I want this functionality in the IDE with code.

Currently, we have code folding where the IDE can close long sections of code and comments. And, we can use Git to manage different versions of code. In web frameworks like Jupyter notebooks, one can interleave markdown, images and programmatic outputs. Imagine working in an IDE and being able to inline UML diagrams during the development process or hyperlinks/screenshots from requirements documents. You can provide traceability within the code. At the same time, these views may be overwhelming at times or too bloated.

Imagine annotating the code using something like XML/HTML as an intermediate coding representation behind the scenes. Layers would be linked to particular query tags for IDE rendering adding within those annotation blocks. At compile time/runtime, queries would extract the source code from its view and operate as usual. However, developer views could have a richness that reduces cognitive overhead while learning and mapping new concepts and can be reduced to its minimalistic representation as well.

I would love to see something like this with a sidebar to toggle: debugging, comments, user-defined regions (e.g. stale code), images, etc.