One piece of feedback – it's not great that the `test_id` is a small sequentially generated integer; it's trivial to iterate across all of the URLs that have been tested.
Acknowledged. I will try to change that in the next update. Though I should mention the data is scrubbed every 3-6 hours. So while the id keeps incrementing, the actual data (past a certain point) can't be scraped. See https://fontsplugin.com/google-fonts-checker/?test_id=999 for example.