The page for editing should look like this:

(from https://matomo.org/docs/email-reports/)

On both 4.0.5 and 4.x-dev the radio buttons are currently missing:

I see the following CSS , but can't find it in the Matomo source:

[type="radio"]:not(:checked), [type="radio"]:checked {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}