woocommerce/plugins/woocommerce-blocks/assets/js/components/product-attribute-control/style.scss

.woocommerce-search-list__item.woocommerce-product-attributes__item {
	&.is-searching,
	&.is-skip-level {
		.woocommerce-search-list__item-prefix:after {
			content: ":";
		}
	}

	&.is-not-active {
		@include hover-state {
			background: transparent;
		}
	}
}