瑜伽論記 7.447

7.447

釋中，不取諸相不念也。由緣餘定地境思惟餘定地，故名於餘作意者，如初靜慮緣上地法上地靜慮緣下地法等，名緣餘定地境。

In the explanation, "not grasping characteristics is non-attention." Regarding "because of taking the realm of another concentration stage as a focal object, one deliberates on another concentration stage, it is named attention to another": just as the first dhyāna focuses on dharmas of a higher stage, or a higher dhyāna focuses on dharmas of a lower stage, and so forth, it is called taking the realm of another concentration stage as a focal object.