It's definitely not the remake, reaps?
The redux has an extended cut, as for Carprenter's "The Fog", I kind of doubt that the Germans would have a version, which hasn't already surfaced anywhere else.
PS: I did a bit of reading and as far as I can tell, the "extended version" of the original "The Fog" on the German disc is nothing more or less than the version familiar to most viewers around the globe.
The film has seen various releases in Germany over the years, some of them cut, so I guess they wanted to point out that the movie on the DVD is the complete cut- in a fairly clumsy way!