wp-includes/blocks/button.php:139Registers the core/button block on server.
function register_block_core_button() { register_block_type_from_metadata( __DIR__ . '/button', array( 'render_callback' => 'render_block_core_button', ) );}Introduced in 6.6.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/blocks/button.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.