This is a Firefox Add-on that hides your contribution graph/streak on GitHub.
It only hides your graph on your profile; everyone else's will still appear.
I've heard from lots of folks that GitHub's contributions graph is very
distracting, leads to bad behaviour, and inspires imposter syndrome. It can
be useful to see other's contributions, but comparing against your own can
get you feeling like you aren't as good a person because your life doesn't
let you have 400 day GitHub streaks.