I noticed today that when you login to Carelink, there is a "Data Export (CSV)" at the bottom of the page.

There has been problems extracting the 770g/Guardian 3 data for use with Tidepool. The ability to export the data and import it could mean Tidepool Uploader can be updated to finally include 770g/Guardian 3 data in the form of the exported CSV.
My exported data CSV (with personal information removed) is available here.
My770gData.csv
Hopefully this information is helpful with adding 770g/Guardian 3 support to the Tidepool Uploader.