The archeologist digging the "gas chamber" trench declares that he has found several yellow tiles (approx. 51mins into the film) and also terracotta brown tiles (and brick) which the viewer is then shown:
Above: screen grab from the documentary showing yellow tile glazed front surface.
Above: The reverse of the tile with what the team announce is a "Star of David" design and hence evidence that they have found the original gas chambers of Treblinka II.
Above: The reverse of a terracotta coloured tile with same "Star of David" design with letter "D" to the left also as embossed into the reverse of the yellow tile fragment.
Above: Terracotta brick from same trench.
Not withstanding the teams assumption that the "Star of David" design on the reverse of the tiles must mean it is Jewish and therefore part of the German gas chamber deception to hoodwink the Jews into believing all was well; one of the Treblinka witnesses clearly states that the tiles on the walls of the gas chamber were white. So not yellow tiles as found by the team therefore there is a discrepancy between the witnesses white tiles and the yellow tiles found in the trench which were declared as being proof of having found the original gas chambers. The witness does mention the floor of the gas chamber being brown which could be terracotta of course and the team found this colour tiles/bricks.
The yellow tiles reminded me of another extermination camp photo I had seen from Auschwitz which also featured yellow and brown tiles/bricks and this is that photo below:
A ceramic tiled heating stove at Auschwitz —featuring yellow facing tiles on a terracotta/brown tiled plinth/base.
This is what I think the team found; fragments from a ceramic tiled heating stove—bearing in mind that the site had been repeatedly blown-up, dug-up and sieved through by locals and Soviet militiamen searching for buried Jewish gold in the camp site.