Yarn already have most of it :

• Latest tweet : Discovery tab has it (https://twtxt.net/discover)
  
• Search for tweets : that one is missing
  
• Mentions : Mentions tab has it (https://twtxt.net/mentions)
  
• Tag : the search tag bar is there (https://twtxt.net/search?tag=mytag)
  
• User : you can see a profile (https://twtxt.net/user/brasshopper/)