Gneis-Süd is considered a district of Salzburg comprising of two post-war settlements, but hardly makes a proper district terms of what look and feel. Gneis-Süd lacks facilities beyond a small stretch of residential zones and has a population of about 1,000 people. It was probably made an administrative district only because it is fairly isolated in the very south of Salzburg, built in an area that was previously swamp land. The area was not extensively used as agricultural land until well into the 20th century (if at all).
Following World War II, many ethnic Germans from Eastern Europe were expelled from their home countries and moved westwards. Thousands of them came to Salzburg and new building developments were started in the mid-1950ies to replace the barracks of the refugees.
In the area of Leopoldskron-Moos, two large housing projects were started: The Eichethofsiedlung and the Birkensiedlung. These two developments are the core of today′s Gneis-Süd. The fact that the district doesn′t even have a proper name and rather refers to another district, Gneis, shows that is really is a satellite settlement in the periphery of Salzburg.
That being said, it is a fairly nice satellite: Gneis-Süd is a middle-class neighbourhood with lots of agricultural land and nature reserves around it. The south can be fairly dark due to the vicinity of the Untersberg (especially in winter). The Almkanal passes the district and its surroundings are characterised by wetlands and swamps, which results in a high abundance of animal and plant species.
German Wikipedia on Gneis-Süd
City of Salzburg, Official Website