WP_Speculation_Rules::add_rule( string $mode, string $id, array $rule ): bool

73	public function add_rule( string $mode, string $id, array $rule ): bool {74		if ( ! self::is_valid_mode( $mode ) ) {75			_doing_it_wrong(76				__METHOD__,77				sprintf(78					/* translators: %s: invalid mode value */79					__( 'The value "%s" is not a valid speculation rules mode.' ),80					esc_html( $mode )81				),82				'6.8.0'83			);84			return false;85		}86 87		if ( ! $this->is_valid_id( $id ) ) {88			_doing_it_wrong(89				__METHOD__,90				sprintf(91					/* translators: %s: invalid ID value */92					__( 'The value "%s" is not a valid ID for a speculation rule.' ),93					esc_html( $id )94				),95				'6.8.0'96			);97			return false;98		}99 100		if ( $this->has_rule( $mode, $id ) ) {101			_doing_it_wrong(102				__METHOD__,103				sprintf(104					/* translators: %s: invalid ID value */105					__( 'A speculation rule with ID "%s" already exists.' ),106					esc_html( $id )107				),108				'6.8.0'109			);110			return false;111		}112 113		/*114		 * Perform some basic speculation rule validation.115		 * Every rule must have either a 'where' key or a 'urls' key, but not both.116		 * The presence of a 'where' key implies a 'source' of 'document', while the presence of a 'urls' key implies117		 * a 'source' of 'list'.118		 */119		if (120			( ! isset( $rule['where'] ) && ! isset( $rule['urls'] ) ) ||121			( isset( $rule['where'] ) && isset( $rule['urls'] ) )122		) {123			_doing_it_wrong(124				__METHOD__,125				sprintf(126					/* translators: 1: allowed key, 2: alternative allowed key */127					__( 'A speculation rule must include either a "%1$s" key or a "%2$s" key, but not both.' ),128					'where',129					'urls'130				),131				'6.8.0'132			);133			return false;134		}135		if ( isset( $rule['source'] ) ) {136			if ( ! self::is_valid_source( $rule['source'] ) ) {137				_doing_it_wrong(138					__METHOD__,139					sprintf(140						/* translators: %s: invalid source value */141						__( 'The value "%s" is not a valid source for a speculation rule.' ),142						esc_html( $rule['source'] )143					),144					'6.8.0'145				);146				return false;147			}148 149			if ( 'list' === $rule['source'] && isset( $rule['where'] ) ) {150				_doing_it_wrong(151					__METHOD__,152					sprintf(