crowdin.net: Entry entity.WitherBoss.name is missing - German translation is "Withern"

The name of the Wither in German is Withern (should be of course Wither).
In crowdin.net the entry entity.WitherBoss.name is missing, so the translation cannot be fixed by the community.

In [MC-126] Nathan Adams wrote:
[Mojang] Dinnerbone (Nathan Adams) resolved MC-126 - Wither as 'Invalid'
Please fix (anyone can do it!) translation issues at http://crowdin.net/project/minecraft

We would like to do so, but since the entry is missing (see the attached screenshot), we cannot translate.

That's not a German-only issue, also in several other languages that entry is missing.