>The link says 'icon-2x to icon-4x' replaced with 'fa-2x to fa-4x' so maybe it's 'fa-1x' ?
Found it defined in our site.css, e.g.
.icon-1x {
font-size: 1.5em;
}
So, it was not a font-awesome thing, it was just unfortunate naming convention.
If it's not broken, fix it until it is.
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