। ॥ १२७ ॥
In plain words
Something exists - self-evident, eternal - that underlies the very notion 'I.' It witnesses all three states of experience, and it is entirely distinct from the five sheaths that seem to wrap around it.
Close to the Sanskrit
There exists something, self-evident, eternal, which is the substratum of the notion 'I' — being the witness of the three states, [and] distinct from the five sheaths.