GitHub has transitioned from using icon fonts to SVG icons across its platform, offering several advantages such as improved rendering quality, accessibility, and ease of integration. SVGs are rendered as images, ensuring crisp visuals at any resolution and eliminating issues like blurry icons in Webkit-based browsers. They also bypass issues related to font overrides, which previously caused layout disruptions for users who changed default typefaces for accessibility reasons. The transition to SVG allows for more flexible icon sizing, easy customization through CSS, and potential for animation, while also reducing CSS bundle bloat by eliminating font-based styles. Despite minor drawbacks like pixel-rounding errors in Firefox and specific requirements in Internet Explorer, the change enhances overall performance and user experience without significant impact on page load times, providing a cleaner and more efficient way to manage icons within GitHub's extensive codebase.