This is an open source media player that can practically handle any file format and one of the world’s most popular free media players. For example, auto-replies to particular messages are possible if you have Thunderbird on your Mac. Consequently, you can perform more tasks with Thunderbird than you can with Mail. In contrast, Mail is just an email client. It is an email client, news client, chat client, and RSS. Mozilla Thunderbird is a free open source platform that is available for the user on Macs and PCs.