sites_group_overrides-1.x-dev/modules/sites_group_media/sites_group_media.links.action.yml

sites_group_media.sites_group_media_relate_page:
  route_name: 'entity.group_relationship.group_media_add_page'
  title: 'Relate media'
  appears_on:
    - 'view.sites_group_media.media_page_list'

sites_group_media_relate_page.group_media_add_page:
  route_name: 'entity.group_relationship.group_media_create_page'
  title: 'Create media'
  appears_on:
    - 'view.sites_group_media.media_page_list'