Add-ons that you install on Firefox have access to certain information. Depending on what the add-on does, it may have access to everything you do or it may have very limited access. When you first install an add-on, Firefox displays what permissions it will have access to. You can always go to an add-on’s page, and scroll down to the Permission section to view them again. If you’d rather not spend so much time viewing permissions, you can install an add-on called Project Insight that lets you view Firefox add-on permissions in one place.
Project Insight makes up for a shortcoming the Firefox add-on manager has i.e., it doesn’t show you the permissions that an add-on has access to.
Firefox Add-On Permissions
Install the Project Insight add-on. It will add a pyramid with an eye icon next to the URL bar. Click it to open the Project Insight page. You can only view permissions for add-ons that are enabled so if you want to view permissions for every single add-on you have installed, you should make sure you’ve enabled them all.
The add-on makes the permissions much easier to read and understand for the average user. For add-ons that can access your browsing history, there’s a dropdown that will give you a list of URLs that it can access.
Project Insight doesn’t add a new feature to Firefox. Firefox has a dedicated internal page about:debugging that lets you view Firefox add-on permissions. The only problem is that the page isn’t easy to read for the average user. Project Insight takes the information that the debugging page shows, and formats it into a more user friendly format. There are helpful icons for every permission that an add-on can have access to. You can jump to an add-on’s options if it has any.
If you click an icon, it will expand to give you details on what the permission entails. For example, if Project Insight says an add-on has access to Add-ons Storage, and you click that particular permission type, it will expand to tell you that the add-on can read and write data to a reserved storage spot. The reserved storage spot is reserved by the add-on. It will take up diskspace but it will be isolated from other add-ons which means they cannot read it.
The explanation for a permission isn’t very detailed but it is enough to give users a general idea of what an add-on is doing.