Restricting plugins and add-ons

[Pelican]

I would like to prevent the use of all plugins and add-ons except for those authorised by us. Where is a good place to start?

I see that blocklist.xml may be related to this. If so how can I prevent blocklist.xml from being updated and undoing my modifications?

[Moonchild]

For this kind of restrictions I suggest you look up Mike Kaply's excellent articles on corporate configuration of Firefox and derivatives.

You probably want to restrict the scope of extensions and plugins to only those supplied with the browser.