Use case or problem
There’s currently no way to distinguish between CSS rules by origin in Obsidian’s JS environment. All stylesheets are read in as plain-text and dropped into the DOM in unmarked <style> elements, so using the document.styleSheets API requires a lot of searching and guesswork for manual searches and is nigh impossible to mess with programmatically (unless you just want to do the same thing to all of them).
Proposed solution
Save the name of the note with the style rules or the stylesheet being imported and add it to the element as a title.
In the dev tools, if I monkey-patch that attribute in, I’m able to do fun stuff like this:
This isn’t a critical feature, but the amount of work that would go into it is minimal (the individual files are already getting imported and added to the DOM, so there should be exactly 1-2 LOC for this change) and it would provide clear labeling for a list that is completely opaque right now.