"From here, one may ascend to the floating Sebelkeh Basilica itself, the most ornate and magical temple in Elona, and the heart of the Lyssan faith." -Outpost description
The Grand Court of Sebelkeh gets its name from the large floating court above the Mirror of Lyss, called the Sebelkeh Basilica. The namesake has been branded in the second game, however.
The Grand Court of Sebelkeh is simple to find on the Domain of Vabbi map in Guild Wars 2; just look for the square north-eastern section of the map. Finding the outpost in the first game is just as easy since it happens to coincide with a primary mission. If you're looking to take pictures, you'll need a skimmer mount in Guild Wars 2 or willing to keep up with the debuff that causes damage over time.