wp-includes/update.php:1047Schedules core, theme, and plugin update checks.
function wp_schedule_update_checks() { if ( ! wp_next_scheduled( 'wp_version_check' ) && ! wp_installing() ) { wp_schedule_event( time(), 'twicedaily', 'wp_version_check' ); } if ( ! wp_next_scheduled( 'wp_update_plugins' ) && ! wp_installing() ) { wp_schedule_event( time(), 'twicedaily', 'wp_update_plugins' ); } if ( ! wp_next_scheduled( 'wp_update_themes' ) && ! wp_installing() ) { wp_schedule_event( time(), 'twicedaily', 'wp_update_themes' ); }}Introduced in 3.1.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/update.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.