Gatekeeper Seals

There is not a lot of information on the Gatekeeper seals, they are one of Khorvaire's greatest mysteries. Most of Khorvaire have never heard of the Gatekeepers, their seals, or the Daelkyr. It's well known from Shadow Marches and Eldeen Reaches legends that the Gatekeepers created the seals that prevent Xoriat from becoming coterminous with Eberron, and keep the Daelkyr trapped in their demiplanes in Khyber. That's about where the "common knowledge" ends.
No one is really sure what the seals actually are. If you asked a dozen gatekeepers, you'd get a dozen different answers. Some will say that the seals are locations, ancient structures found in the deep places of the world, massive rune-carved stones infused with byeshk ore and placed in powerful manifest zones. Other stories tell of small disks worn as pendants by the gatekeepers, each connected to a particular daelkyr. Some of those stories also claim that the bearer of the pendant can feel the daelkyr it's tied to, and siphon it's power, though down this road madness lies.
One story claims that the mightiest druids turned themselves into trees, and that these trees are themselves the seals. One popular folk song sung in the Shadow Marches claims that it is itself the seal, and that as long as it is sung the daelkyr will never return. Some believe that the seals are the light held in the dragonshards scattered throughout the Marches, and that House Tharashk's mining risks dooming us all, much like in Q'barra.
All of the stories agree that powerful magic was used to hide the seals, lest they be found and destroyed. This seems to be the case, divination magic has proven unable to reveal any information about the seals or what form they take. The variety in these tales could indicate that even the Gatekeepers don't know what the seals are, perhaps they hid this knowledge to prevent it from being destroyed. Alternatively, perhaps they are purposefully spreading misinformation to protect the seals.
It could even be possible that there is only a single seal, and all these others are simply red herrings.