wp-includes/general-template.php:2224Gets number of days since the start of the week.
$numintfloatfunction calendar_week_mod( $num ) { $base = 7; return ( $num - $base * floor( $num / $base ) );}Introduced in 1.5.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/general-template.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.