If you are using Google Chrome as your default browser, then you will notice that–clicking on any mailto: links will open either in Gmail.com website or it does nothing. The behavior what it needs to be done when clicking on those special links is termed as protocols, and the programs they use are called handlers.
By default thunderbird application won’t send spam/Junk mails directly to the Junk folder. Every time you receive junk mails on your thunderbird application, it just mark that mail with junk icon (flame icon) on your inbox. In this guide I will show you how to send junk mails automatically to your thunderbird junk folder.