InternalLinkTypeMainWebApp

The link is a link to the main Web App of a bot. Call Client.search_public_chat with the given bot username, check that the user is a bot and has the main Web App. If the bot can be added to attachment menu, then use Client.get_attachment_menu_bot to receive information about the bot, then if the bot isn't added to side menu, show a disclaimer about Mini Apps being third-party applications, ask the user to accept their Terms of service and confirm adding the bot to side and attachment menu, then if the user accepts the terms and confirms adding, use Client.toggle_bot_is_added_to_attachment_menu to add the bot. Then, use Client.get_main_web_app with the given start parameter and mode and open the returned URL as a Web App