The Index Page is the page shown when the root index / is accessed.
For each siteaccess, you can configure IndexPage, as in eZ Publish 4.x. Put the parameter
index_page in your ezpublish.yml file, under the right siteaccess category.
ezpublish: system: mygreat_site: languages: - eng-US #The page to show when accessing IndexPage (/) index_page: /yourURIPage
|If not specified, the index_page is the configured content root.|