wp-includes/class-wp-block-bindings-registry.php:242Checks if a block bindings source is registered.
$source_namestring|nullbool public function is_registered( $source_name ) { return isset( $source_name, $this->sources[ $source_name ] ); }Introduced in 6.5.0. One change between 6.7.7 and 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
$source_name retyped from string to string|null.verified against sourcesrc/wp-includes/class-wp-block-bindings-registry.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.