The utilities-icons module uses HTML Entities (special characters) for simple shapes. For example for star ratings the entity ★ can be used to create a solid star (★). The corresponding icon utilty would be u-icon-star-operator. Correspondingly, the html entity ☆ can be used to to create empty stars (☆). Since these are vector shapes resolution stays crips at any zoom level.
Note that some html entities, like thin space &thinsp do not have a visual rendering, but can be used to alter content rendering.
The soft hyphen html entity will only render in specific contexts.
See Installation.
See Usage