[fedups]

I believe Santosh83 means even if you leave it on, it will be anonymized performance data

[brador]

You can't anonymize data in transit since it requires a sender IP which makes the sent performance data susceptible to interception and analysis by intermediaries.

[floatboth]

It's boring data, encrypted in transit (HTTPS). About the only thing intermediaries can learn is that someone used Firefox at the time of the request.