No, note the desktop position and C++ requirement. Also note Qt QML being mentioned. This is not about maintaining a web site. This is straight about creating desktop GUI applications (like downloader and etc.).
So in other words GOG is or will be running some Linux server(s) and want some one to create GUI applications for that purpose. Perhaps related to special GOG related server maitanence needs. Perhaps some GUI applications to edit game descriptions or mainain the GOG library/database of games?
What ever it is the person won't be working on actual Linux support for actual games. There is no way they could get the games to run on the Rapsberry Pi. So we sadly won't see Linux support on GOG :(
Future_Suture that is VERY good news about CryTek, if only GOG were as open minded as them!