netbox-community-netbox/netbox/project-static/materialdesignicons-5.4.55/scss/_icons.scss

@each $key, $value in $mdi-icons {
    .#{$mdi-css-prefix}-#{$key}::before {
        content: char($value);
    }
}

.#{$mdi-css-prefix}-blank::before {
    content: "\F68C";
    visibility: hidden;
}