Why 3 icon bars in navbar toggle

Can anyone explain the reason for having 3 (empty) icon-bars in navbar toggle? To me, it looks like it just complicates styling (the text "Menu" comes from CSS

.plone-navbar-toggle .icon-bar::after {
    content: "Menu";

I think it's for styling a "hamburger-menu" based on Bootstrap 3 Framework

Sounds like a possible reason.

That said: I would have done it differently, favicon or unicode character… maybe

.plone-navbar-toggle .icon-bar::after {

That is the reason :wink:
Here is the old Bootstrap Code