Twitter has launched an audio-only broadcasting feature so that users can broadcast their voice to their followers without being seen. The feature is currently publicly available for all iOS users of the Twitter and Periscope. Users can go to the "Go Live" button on the compose screen to use this audio broadcast option.
However, they need to update their iOS Twitter or Periscope app to the latest version. This new feature seems like Twitter's attempt to introduce a new type of live streaming platform other than live video. Podcasts are becoming quite popular in the recent years, hence this move by Twitter seems a reasonable one to get a share of the growing industry. Twitter is also testing out a new design that will add the "Explore" tab and Bookmarks to the desktop site's home page. These features are currently being rolled out to only a small number of users. Twitter asked for feedback from users who were able to see those features in their accounts.
The Explore tab has a bunch of things like Moments, trends, search and other insights to keep the user up to date about the current happenings at a quick glance.