wp-includes/rest-api.php:1581Determines if a given value is integer-like.
$maybe_integermixedboolfunction rest_is_integer( $maybe_integer ) { return is_numeric( $maybe_integer ) && round( (float) $maybe_integer ) === (float) $maybe_integer;}Introduced in 5.5.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/rest-api.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.