Category
Magento\Catalog\Model\Indexer\Product\Category
What it does
This indexer maintains the relationship between products and categories in Magento 2.
It rebuilds or updates the catalog_product_category index table whenever products are assigned to or removed from categories, ensuring accurate product-category associations for catalog browsing and filtering.
Developers interact with this when triggering reindexing operations or extending category-product relationship functionality.