wp-includes/rest-api.php:1339Parses a 3 or 6 digit hex color (with #).
$colorstringstring|falsefunction rest_parse_hex_color( $color ) { $regex = '|^#([A-Fa-f0-9]{3}){1,2}$|'; if ( ! preg_match( $regex, $color, $matches ) ) { return false; } return $color;}Introduced in 5.4.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/rest-api.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.