Wealthsimple Trade Export to Excel (CSV XLS file) by JWallet

This extension does not expose your data to an external tool or communicate in any way to a another service. It only provides feature for the current tab, and its actions are limited to that tab only. It will use your session to be able to fetch all required info in order to make the feature work.

This addon is open source and available on GitHub. You can take a look at the code by visiting the addon homepage link. You may also want to build the extension yourself, just download the source code, build it, and add it to Firefox or Chrome using the debug addon tool.