The extension Mozex, for Firefox and Mozilla, is a very useful extension, written by Tomas Styblo, that let you handle with external applications many internet protocols and many functions (for ex. use of external editor to view the html source, the ftp links, the telnet links etc.).
The last official version of Mozex is the 1.07, made in 2003, that you can downloaded at, where you can find also the complete documentation about it and also news about other developments.
The 1.07 version is not fully compatible with the Firefox version => 0.9: it works, but you can't see it under Tools --> Extensions , you can uninstall it with the automatic system of Firefox, you can't see the options panel (some of these problems can be solved using other extensions).

Here you can find a modified version, with these features:

This version CAN'T works with Mozilla Suite and with Firefox < 0.9.
The version 1.07.9 works with Firefox 1.0 - 9

Download mozex-1.07.9

You can find a version of this extension with a patch for the utf8 textareas at this address.