Not sure what you are asking... Stuff by Mozilla, stuff for Mozilla, what?
Firefox is fairly secure, but all my security stuff is by different people... not that what I call security is really security. I'm talking about stuff to protect my system (firewall, A/V, A/spy, stuff like that).
Thts a nice defragger, but it doesnt have the nice scheduling features that the full version has which lets you set the thing to run in the background and keep fragmentation under check.