wp-admin/includes/class-wp-site-health.php:3467Checks if the current environment type is set to 'development' or 'local'.
bool public function is_development_environment() { return in_array( wp_get_environment_type(), array( 'development', 'local' ), true ); }Introduced in 5.6.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-admin/includes/class-wp-site-health.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.