The 'Discover' tab was unveiled at Facebook's F8 2017 conference earlier this year for the US market. "...after promising results in the US, we have decided to launch the Discover Tab in additional countries, including India," Facebook said in a statement.
Users, upon tapping on the Discover icon on the lower right hand corner of the Messenger Home screen, can browse recently visited businesses, featured experiences and categories.
Messenger bots are used by businesses to send updates/communication to users on a variety of subjects. For example, if a user subscribes to a bot of a FMCG company, he/ she can get the latest news/updates and offers from the firm on Messenger.