Mozilla has published a list of 10 Firefox add-ons that hinder the browser’s performance the most.

The list ( https://addons.mozilla.org/en-US/firefox/performance/#addon-11 ) shows how much each add-on slows down Firefox at startup.

Ironically, an add-on called “FastestFox – Browse Faster” is on the list, together with several very popular ones such as the developer-oriented Firebug and bookmark synchronizer Xmarks.

The slowest add-ons on the list, FoxLingo – Translator/Dictionary and Firebug, slow down Firefox’s startup by a whopping 74%.

The list is a result of a recent initiative by Mozilla to put a stop to performance-slowing add-ons. Mozilla announced it will perform automated performance tests of the top 100 add-ons hosted in its add-on gallery every week and display warnings for add-ons that slow Firefox’s startup time by 25% or more.