Web Page Fixer Examples

Here are some of the main problems this Firefox extension can fix:

Office Web Components
These are supposed to show spreadsheets and other content, but in most browsers it will only show "Missing: Microsoft Office Web Components". (examples) If this extension is installed, firefox can let you extract and view the hidden data.
Symbol Font Fix:
In Firefox 3.0+, and many other browsers, the font system will not turn standard characters into other symbols. This presents a problem if a site depends on the symbol font to turn letters into symbols. For example, the text in this box won't show up as "Δπμ", as it is designed to, instead it will correctly show "Dpm". There is an option enabled by default in this extension that will turn these symbol font texts into standard unicode symbols so they display as they are supposed to.

Dpm

(This should show up as "Δπμ", not "Dpm")
Another useful feature is the option to set the Firefox "Do this automatically for files like this from now on" to always open automatically. It will not keep asking while "do this automatically" is already checked!