wp-includes/class-wp-theme-json-resolver.php:709Determines whether the active theme has a theme.json file.
bool public static function theme_has_support() { _deprecated_function( __METHOD__, '6.2.0', 'wp_theme_has_theme_json()' ); return wp_theme_has_theme_json(); }Introduced in 5.8.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-theme-json-resolver.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.