The easy way to download and convert Web videos from hundreds of YouTube-like sites.
This works also for audio and picture galleries.
The Web Developer extension adds various web developer tools to the browser.
The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.
Xmarks is the #1 bookmarking and open tab add-on. Keep your bookmarks, and open tabs backed up and synchronized across computers and browsers. Mobile phones with Premium access. Utilize LastPass to sync passwords!
FireShot Webpage Screenshots captures webpage screenshot entirely (see demo: http://bit.ly/RlBQMV)
The screenshot can be quickly annotated and:
+ Saved as PDF/PNG/GIF/JPEG/BMP
+ Sent to clipboard
Advanced Eyedropper, Color Picker, Gradient Generator and other colorful goodies...
Use tamperdata to view and modify HTTP/HTTPS headers and post parameters...
Draw a ruler across any webpage to check the width, height, or alignment of page elements in pixels.
YSlow analyzes web pages and suggests ways to improve their performance based on a set of rules for high performance web pages.
http://yslow.org is the official open source website.
Attempting to reduce both Browser and Flash RAM Memory usage. Memory Fox will promote the increase of available RAM memories for other application processes. Hopefully, fostering any attempts of Memory Recovery and Retention.