Quick Asana handles the following user data:

Asana Credentials
The Asana personal access token that you supply in extension preferences is stored in Firefox Sync storage, along with your selected workspace and assignee IDs fetched from Asana.

Browser Tab Data & Clipboard Contents
When the extension is clicked, it captures the active tab's page title, URL & a screenshot of the visible area, or the current contents of the clipboard if shift is held. These are transmitted to Asana, where they are subject to Asana's privacy policy and terms that you agreed to when you created your Asana account.

No data is transmitted to the author or to other services. Quick Asana does not use any analytics systems or other tracking mechanisms beyond that provided automatically by Firefox. Quick Asana does not capture any browser data unless it is clicked, and never modifies web pages or browser configuration.