`endpoint_id`: `GET /api/:version/groups/:id/registry/repositories` ### Context You can use the container registry API to return a list of container image repositories and their associated tags for a given groupID. ### Problem to solve Returning a list of tags for every image repository is an expensive query and can result in slow response times that are beyond GitLab's tolerated apdex threshold of 1 second. This endpoint continues to display very poor performance - the p75 is over 5 seconds, with p99 sometimes spiking up to over 20 seconds.  [source](https://log.gprd.gitlab.net/goto/c4c90a2fa765fa814ea0f81cb8ce8208) ### Proposal Update the API to only return a list of image repositories. The tags can be pulled for a specific image repository rather than generating every tag for every group. This means that the [`GET /groups/:id/registry/repositories`](https://docs.gitlab.com/ee/api/container_registry.html#within-a-group) endpoint will no longer support the `tags` and `tags_count` parameters. To obtain the tag count/list, users can use the [`GET /registry/repositories/:id`](https://docs.gitlab.com/ee/api/container_registry.html#get-details-of-a-single-repository) endpoint, which will continue to support the `tags` and `tags_count` options as it does today. Since this may introduce a breaking change, we'll need to consider this change for milestone 15.0