Hello mnap,
Thanks for using our plugins and welcome to the forums!
Thank you for your feedback on the German translation. I have checked several sources and all of them showed that both die E-mail und das E-mail are valid, accepted formats.
Me being a user of the German language as well, I prefer using das E-mail. So I guess this is totally up to preference. Of course you can use in your translation file your preferred version.
Thanks again and let me know if you have any further thoughts or questions regarding this or any other translation strings. We are working hard in raising the quality of our translations and any help in this is much appreciated.
Cheers,
Andras