grav-admin-first/user/plugins/admin/themes/grav/scss/template/_fonts.scss

// RocketTheme Apps Support
@include font-face('rockettheme-apps', '../fonts/rockettheme-apps/rockettheme-apps');

i.fa-grav, i.fa-grav-spaceman, i.fa-grav-text, i.fa-grav-full,
i.fa-grav-logo, i.fa-grav-symbol, i.fa-grav-logo-both, i.fa-grav-both,
i.fa-gantry, i.fa-gantry-logo, i.fa-gantry-symbol, i.fa-gantry-logo-both, i.fa-gantry-both {
    font-family: 'rockettheme-apps';
    speak: none;
    font-style: normal;
    font-weight: normal;
    font-variant: normal;
    text-transform: none;
    line-height: 1;

    /* Better Font Rendering =========== */
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

// Grav
.fa-grav-logo:before, .fa-grav-text:before {
    content: "\61";
}
.fa-grav-symbol:before, .fa-grav:before, .fa-grav-spaceman:before {
    content: "\62";
}
.fa-grav-logo-both:before, .fa-grav-both:before, .fa-grav-full:before {
    content: "\66";
}

// Gantry
.fa-gantry-logo:before {
    content: "\64";
}
.fa-gantry:before, .fa-gantry-symbol:before {
    content: "\63";
}
.fa-gantry-logo-both:before, .fa-gantry-both:before {
    content: "\65";
}