Brahmavidyā is the knowledge of Brahman taught in the Upaniṣads, distinguished from the lower knowledge of the sciences and the ritual. The Muṇḍaka Upaniṣad says that the knower of Brahman becomes Brahman. It is not information about Brahman but the realization of the self as Brahman.
Brahmavidyā
The knowledge of Brahman: the highest knowledge, which the Upaniṣads say liberates the knower.
Also: Brahma vidya