New to obsidian : I don't understand negation in path

I want to exclude src/node_modules from Graph so I tried

-path:“src/” -path:“src/node_modules”

but I still see a bunch of readme.md files from there.

It looks like you used “smart” (proper typographical) quotation marks instead of straight ones. Maybe you had straight ones and they got converted when you pasted in the forum, but check to be sure.

If you had the wrong quote marks in your vault, try it with parentheses () instead to avoid that problem.