OMDb key
Ratings come from the free OMDb database. By default the extension shares one key, which is limited to 1,000 lookups a day across everyone using it. If badges stop appearing, add your own free key for a private 1,000 a day.
Get a free key (pick the free tier, activate it from the email), then paste it here.
The key is stored only in this browser and sent only to omdbapi.com with each lookup. Already-fetched ratings are remembered locally, which keeps your daily usage low.