In the documentation of lqe and dlqe, it states:

produces a state estimate x_e that minimizes the expected squared error using the sensor measurements y.

From my understanding of theory, this is quite inaccurate/imprecise.
A better wording would be:

produces a state estimate x_e that minimizes the generalized variance of x - x_e using the sensor measurements y.

Source:
https://en.wikipedia.org/wiki/Generalized_variance
https://arxiv.org/pdf/2103.07275

Another wording would be that it minimizes the trace of the covariance matrix x - x_e,
but thinking in a generalized variance is more catchy.