It is there. The first tab is "Get Addons". It has a search bar that you can use to search and install addons/plugins. It uses the same pages that FF 2 used: https://addons.mozilla.org/en-US/firefox/
Thank you 67GTA.
I found some addons, and plugins - but are the plugins here ready for Mint?
Take RealpPlayer - this is a BIN package..
OK if I want it, I can learn how to install BIN package.
I was aware of the about:plugins. I was more after how to install new plugins.