It's Excalidraw, but the pencil tool matches the size of other tools.
Deployed at http://locofocos.com/excalidraw-opinionated-pencil/ or https://locofocos.github.io/excalidraw-opinionated-pencil/ if I forget to renew my domain.
Some folks are trying to solve this problem over at excalidraw#3693 but nobody can make progress. I just want something I can use for drawing.
rm -rf docs
yarn build
mv build/ docs/
then commit and push