Many years ago, the people in charge of the Debian project created the Iceweasel browser as a derivative product of Firefox, since there were some problems with Mozilla due to issues of trademark rights. Today it was announced that Iceweasel will disappear as such, calling Mozilla Firefox again the browser of the Debian operating system.
This ends a 10-year mini-conflict between Mozilla and the Debian project, which I call a mini-conflict because itThe only thing that changed in Iceweasel was the name, some registered trademark and little else, being otherwise identical to the Firefox browser.
It has been a long time since the conflict occurred, as at that time Firefox was only in version 1.5, now the stable version is version 44. It has been 10 years in which many things have changed, such as the collapse of Internet Explorer or the emergence of Google Chrome.
The reason the Iceweasel name has been discontinued is that Mozilla has left behind its old claims of naming policy and you have accepted the Debian terms. It is also more interesting for Mozilla not to have enemies and to have allies to support it in its fight to be the browser with the largest market share in the world.
Debian users will not notice any difference when browsing the Internet, since it will only change the name of the browser, everything else being practically the same as always. If you know English, you can see the full news on the Debian bug blog by accessing from here.
Now that Mozilla has backed off on this issue, the same could happen with the Icedove email manager, which could disappear in favor of Mozilla Thunderbird. But that it's just speculation and there is no confirmed news about Icedove.