I think it would be nice to see the ability to manipulate cookies through the browser. When programming I often have to echo the cookie value or write a static cookie to test authentication and security. A way to list/edit session data would be nice too.
-Ed

@ Ed M

Maybe you can adapt this program to provide the info you need for cookies.
http://www.nirsoft.net/utils/mzcv.html

The information in sessions is stored in the prefs.js file.

user_pref("kmeleon.plugins.sessions.ask_autoload", false);
user_pref("kmeleon.plugins.sessions.autoload", false);
user_pref("kmeleon.plugins.sessions.cleanShutdown", false);
user_pref("kmeleon.plugins.sessions.maxUndo", 5);
user_pref("kmeleon.plugins.sessions.openStart", "");
user_pref("kmeleon.plugins.sessions2.Last Session.count", 1);
user_pref("kmeleon.plugins.sessions2.Last Session.window0", "19	51	36	768	660			0	-1	");
user_pref("kmeleon.plugins.sessions2.Last Session.window0.count", 1);
user_pref("kmeleon.plugins.sessions2.Last Session.window0.tab0", "8	7			http://www.perigee.net/	Welcome to Perigee.net	http://www.nirsoft.net/utils/index.html	Freeware Tools and Utilities for Windows	http://www.nirsoft.net/web_browser_tools.html	Freeware Web Browser Tools Package	http://www.nirsoft.net/utils/mzcv.html	MozillaCookiesView: Cookies Manager For Mozilla/Firefox/Netscape Browsers	http://kmeleonbrowser.org/forum/list.php?1	K-Meleon :: General	http://kmeleonbrowser.org/forum/	K-Meleon	http://kmeleonbrowser.org/forum/list.php?4	K-Meleon :: K-Meleon Improvement requests	http://kmeleonbrowser.org/forum/read.php?4,82363	K-Meleon :: K-Meleon Improvement requests :: Cookie Editing	");
user_pref("kmeleon.plugins.sessions2.Previous Session.count", 1);
user_pref("kmeleon.plugins.sessions2.Previous Session.window0", "3	51	36	768	660			0	-1	");
user_pref("kmeleon.plugins.sessions2.Previous Session.window0.count", 1);
user_pref("kmeleon.plugins.sessions2.Previous Session.window0.tab0", "5	3			http://www.perigee.net/	Welcome to Perigee.net	http://kmeleonbrowser.org/forum/list.php?1	K-Meleon :: General	http://kmeleonbrowser.org/forum/	K-Meleon	http://kmeleonbrowser.org/forum/list.php?4	K-Meleon :: K-Meleon Improvement requests	http://kmeleonbrowser.org/forum/read.php?4,82363	K-Meleon :: K-Meleon Improvement requests :: Cookie Editing	");
user_pref("kmeleon.plugins.sessions2.list", "Previous Session,");

I can edit the cookies in the text file though the main issue is that the browser needs restarting to-reread the file.