I went to put in an outlet with charging ports and found this monstrosity behind the wall plate. The box is filled with expanding foam, I'm guessing as some kind of support? Then painted all over. I scraped it all out, put in outlet spacers and its much better. I think there's foam around the box too, but I'm not gonna worry about that (yet).
Now I get to spend next weekend replacing all the outlets in the house just in case there's any more sketchy "fixes" 🫠
After cleaning and replacing:
To add to what you suggest: I make a habit of verifying and writing the breaker number on the back side of the faceplate each time I have to remove/replace one.
Always re-check before digging into the wiring obviously, but man I don't know how many trips up and down the basement stairs that has saved me over the years!