What does the `is.selected` assertion refer to?

[dwjohnston]

You docs suggest that it uses a :selected psuedoclass selector - however, I can't see that :selected is actually a psuedoclass. https://developer.mozilla.org/en-US/docs/Web/CSS/Pseudo-classes#input_pseudo-classes

Essentially what I'm wanting to use the is.selected assertion on, is checking that an element with the role tab has aria-selected="true"

[dwjohnston]

For anyone who is seeing this, the assertion I use instead is:

(Cypress:)

.should("have.attr", "aria-selected", "true")

[dwjohnston]

Similarly, what does the is.visible selector do? I can't see that :visible is a psuedoselector.