Hello! I am an engineer on the streamlit team and can answer this question.
The data that is sent to fivetran is for our analytics/telemetry. This data helps us make streamlit better for everyone by better understanding how users are using various components of the library. Without this data, our job becomes much more challenging as we would struggle to see what our users are having issues with and we’d also have less data knowing what our users are really enjoying and where we should continue to invest. The data being sent complies with GDPR and is stripped of any personal information. For example, we can see that a function is called with 2 arguments of X size, but we don’t actually see the strings you passed to it.
With that being said, if you still want to disable this, you can do so by adding the following in your config.toml:
[browser]
gatherUsageStats = false