What the extension does
The extension fetches three exports from DEGIRO that you would otherwise download yourself: the Transactions overview, the Account overview and the Portfolio overview. It uses the session you are logged in to DEGIRO with, in your own browser, from your own internet connection. The exports are forwarded directly to your Insiviz account and processed there in the same way as a manual CSV import.
Syncing only happens while you are logged in to DEGIRO: when you open a DEGIRO page (at most once every six hours) or when you click “Sync now” yourself.