The Smart References Google Docs Add-On by Sealion Software does not store data from documents with which it is used outside of the Google Docs app.
The Add-On runs on Google’s servers and in users’ browsers. It accesses the documents for which it is installed via Google’s APIs in order to show a document outline in the sidebar and to create and update references in the document. This data is not transmitted to Sealion Software or any other party. References are stored inside the document in the form of hyperlinks.
Please address any other privacy questions to firstname.lastname@example.org