non-text content

any content that is not a sequence of characters that can be programmatically determined (opens in a new tab) or where the sequence is not expressing something in human language (opens in a new tab)

Note: This includes ASCII art (opens in a new tab) (which is a pattern of characters), emoticons, leetspeak (which uses character substitution), and images representing text

Source: WCAG 2.2 definition of “non-text content” (opens in a new tab) (W3C)