wp-includes/style-engine/class-wp-style-engine-css-rules-store.php:134Gets a WP_Style_Engine_CSS_Rule object by its selector.
$selectorstring$rules_groupstringoptional''WP_Style_Engine_CSS_Rule|null public function add_rule( $selector, $rules_group = '' ) { $selector = $selector ? trim( $selector ) : ''; $rules_group = $rules_group ? trim( $rules_group ) : ''; // Bail early if there is no selector. if ( empty( $selector ) ) { return null; } if ( ! empty( $rules_group ) ) { if ( empty( $this->rules[ "$rules_group $selector" ] ) ) { $this->rules[ "$rules_group $selector" ] = new WP_Style_Engine_CSS_Rule( $selector, array(), $rules_group ); } return $this->rules[ "$rules_group $selector" ]; } // Create the rule if it doesn't exist. if ( empty( $this->rules[ $selector ] ) ) { $this->rules[ $selector ] = new WP_Style_Engine_CSS_Rule( $selector ); } return $this->rules[ $selector ]; }Introduced in 6.1.0. One change between 6.7.7 and 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
WP_Style_Engine_CSS_Rule|void to WP_Style_Engine_CSS_Rule|null.verified against sourcesrc/wp-includes/style-engine/class-wp-style-engine-css-rules-store.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.