> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://support.thumbnailtest.com/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# What is the “Control Group” in these experiments?

The tool will always include the original thumbnail or title in the experiment to ensure that you know if your original was better than your new variations.