You can always even check the code that’s running on your own computer. If you installed Homebrew in /usr/local the relevant files are /usr/local/Library/Homebr

You can always even check the code that’s running on your own computer. If you installed Homebrew in /usr/local the relevant files are /usr/local/Library/Homebrew/utils/analytics.sh and /usr/local/Library/Homebrew/utils/analytics.rb.