Inject alt attribute text where possible. If the element is an icon font and doesn't support alt attributes then use ARIA markup.

Places where alt attributes / ARIA markup is missing:

• App close button. Closing an app is difficult. The screen reader does not speak the close button.
• Trinity icons are just empty span tags, icons without alt attributes. Cannot navigate to them. There is no way to do alt attributes for icons but you can add a hidden span element maybe.
• Views in an app: list, tree, thumbnail. These are icons only. Add a text label, alt attribute or something that a screen reader can speak.