Harry himself knew how to cast a Sensory Barrier. Although he could not manage one that large, he still understood the magic itself.
And Ravenclaw's legacy also contained the original form of this magic.
This magic had existed as far back as the ancient magical system, and Rowena Ravenclaw had mastered it as well. However, the version from that era differed considerably from the current one. Harry could not immediately tell which was better overall.
One thing was certain, though: the Sensory Barrier in Ancient Magic was more difficult to set up and required a higher level of mastery over magic.
In return, the Sensory Barrier in the ancient magical system lasted longer.
As for its concealing effect, judging by Harry's current impressions, the modern Sensory Barrier was probably more effective. After all, the essence of this magic-the Confundus Charm-had been repeatedly studied and strengthened by wizards over all these years.
It was the foundation of the separation between the Wizard World and the Muggle world.
After more than a thousand years of improvements by hundreds upon thousands of outstanding wizards, it would have been rather strange if it had not become more powerful.
Comparatively speaking, the number of wizards was still increasing. After all, the human population as a whole continued to grow.
With enough wizards, there would be no shortage of sources of magical power. Although the number of high-level wizards never seemed to rise, making up for quality with quantity was still an option.
Thus, it was only natural for the magic to be refined into a new version that was less difficult and more powerful, at the cost of needing constant replenishment.
Yet now, as Harry sensed the Sensory Barrier Dumbledore had left behind, which still held a considerable amount of magical power, he discovered that