This is the token provided by the BotFather at Telegram when you create a bot there. This token is needed if you want TAD to send collaboration notifications to a Telegram channel. Apart from this token, you would also need to give a project property called TEL_CHANNEL , which has the Channel ID of the Telegram channel into which the notifications are sent. Also make sure that the bot is actually a member of that channel too.

Explained in detail here: telegram messages