Sorry this is a little late…
WCAG 2.0 requires sufficient contrast for text and images of text. Modern web content increasingly uses icons, emojis, and other graphical elements to convey content, meaning, and functionality. As such, adequate contrast for such elements is critical. WCAG 2.1 is likely to introduce contrast requirements for icons, but in the meantime ensure that such elements are readily visible and identifiable for all users.
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