"Simple framework for creating browser extensions. Only Opera supported now."

I merged my Pinboard extension with this one. (added using the current text selection as the bookmark description)

"YSlow analyzes web pages and tells you why they're slow based on the rules for high performance web sites. YSlow is a Firefox add-on integrated with the popular Firebug web development tool."

"A Firefox extension that displays keyboard shortcuts as you move your cursor over toolbar buttons and other UI widgets."

Besides NVU and STTS they've also developed a couple of interesting Firefox extensions - the full screen one looks particularly useful.

"Makes unused tabs fade with age and highlights the selected tab."