Magento Wishlist supports the GraphQL query feature. You can refer to the module-wishlist-graph-ql from the Magento core code to get more info on the specific query feature.
The schema.graphql file for the Wishlist module will be available at the path, vendor/magento/module-wishlist-graph-ql/etc/schema.graphqls
You must have enabled the Wishlist feature to get the output of the query by Stores -> Configuration -> Customers -> Wish List -> General Options -> Enable -> Yes.