How to show the ALT content in an Inoc4 PWA?

is there a way on an Ionic4 PWA to show the description of a button or of an icon (when the user goes with the mouse over it) with the ALT tag?
Probably it works only with images.

Or there are other ways to do this?

            <ion-col size="3">
              <ion-button expand="full" (click)="changeUserRole()" color="warning" alt="Change the role of the user">
                <ion-icon name="ribbon"  alt="Change the role of the user"></ion-icon>

Thank you very much