The add-in never collects, stores, or transmits information that can be used to identify you, except for PayPal data: If you use PayPal to contribute, then PayPal provides Stock Connector with the email address and name from your PayPal account.
The add-in does collect anonymous information about how the add-in is used, such as how often it's launched and which buttons get clicked. These logs are collected through the Google Analytics web service. To distinguish users from each other, the add-in generates a random number for each user, which is stored on your computer and can be removed by clearing your cookies. The information collected is used only to improve the quality of the add-in and is not sent or sold to any third party.
The data provider is IEX. In order to retrieve the stock quotes, the add-in sends IEX the list of stock tickers for each refresh.