You could always ask someone who works on Google Fonts. I did just that. The answer is they don't use the logs for much apart from counting how many people use each font to draw pretty graphs.
Doesn't mean that won't change in the future though. But log retention is only a matter of days, so they can't retrospectively change what they do to invade your privacy.
Doesn't mean that won't change in the future though. But log retention is only a matter of days, so they can't retrospectively change what they do to invade your privacy.