The old Twitter icon with the bird was still displayed in various places.
What these places have in common is that the icon is automatically loaded with a so-called “codepoint” from an icon font.
Examples:
- The “Shariff” buttons.
- Content generated via HTML in the flexible element, e.g., in the footer area.
The CSS was extended with a special rule so that the X icon now appears in places where the old Twitter bird was previously displayed via the icon font.