I used to refactor (popular) wordpress plugins. I don't do it but I use a chromium extension (not a popular one though) which I realized was using half of my ram. Pretty hot for a leak.
The source is tiny, so tiny you wonder how this thing can leak at all, there's nothing except one simple loop.
Turns out it was a piece of debugging code. The whole production source is full of them, 90% of them are harmless except that one line.