The chamber is spacious, dug out of the rock. Patience is a desert planet, redolent with precious minerals valuable for starship and megastructure construction. In some of the mines you can pick up nearly-pure samples of ore.
This cavern is extremely humble by comparison. Many inhabitants of Patience can identify ores by sight, and this particular cave is nearly devoid of them. Instead of mineral riches, it is covered in cultural ones. Art of the little natural farming possible on Patience is shown. Gheap are herded across the polished stone walls, along with scenes of harvesting edible cave-moss that locals turn into bread. River and aquatic motifs abound as well, though Patience is a desert world with remarkably few rivers.
And the builders of the tomb saw fit to hollow out the center into a knee-deep pool. A Westerly automated environmental management kit was built into a small altar in the far end of the pool. And it has performed its duties of keeping the pool's artificial ecosystem running smoothly for the past twenty-eight years. There are aesthetically-pleasing plants decorating the bottom of the pool, and they sway slightly in the 'tide' produced by the environmental manager.
On a normal world, this would be a slightly eccentric shrine.
On Patience, a world where water is the main cost of living, it's worth several years' of a laborer's income.