wp-includes/class-wp-block-list.php:73Returns true if a block exists by the specified block offset, or false otherwise.
$offsetintbool #[ReturnTypeWillChange] public function offsetExists( $offset ) { return isset( $this->blocks[ $offset ] ); }Introduced in 5.5.0. One change between 6.7.7 and 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
$offset retyped from string to int.verified against sourcesrc/wp-includes/class-wp-block-list.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.