Just initializing new latest installation. The doc https://www.home-assistant.io/getting-started/onboarding/
shows a + icon at lower right and discusses its use, whereas http://homeassistant.local:8123/config/integrations has “Do you want to stay logged in?” in that corner with no + insight.
Has some other method replaced the +?
Update to my question: It turns out that clicking No to the "Do you want to stay logged in? choice clears away that area and exposed the “+” icon. Perhaps this front end page needs revision.