I'm not sure if ward technology (if that's even a thing) has ever been discussed, even in the JoJ, but I had some neat ideas, or atleast I thought they were neat.
Basically wards are magically empowered flowers that can be used as a sort of magical security camera. They originated as a primitive magic where seeds would be placed in a gemstone, which would later be named a
and empowered by the crystalline magic within. The seeds were then drawn out with some kind of spell and would instantly grow upon being planted or just hitting the ground, creating a plant that would provide vision of its surroundings to whoever looked in to the sightstone.
Later on when magic became used to slip past guards and wards a new kind of sightstone was created from rubies;
. This one caused the flowers to be further empowered, allowing them to see through magical illusions and the like, but at the cost of being more crystalline than the usual wards. This let them last longer but also made them stick out like a sore thumb.
could be considered an alternate version of that.
That's my silly hypothesis about wards and what the hell they even are, but hey I might be wrong, just thought the gameplay elements of wards actually could infer what they're actually like in the lore.