What is this field at the bottom of the app closing screen on my iPhone?

I am using an iPhone X with iOS11.3.1 and today I wondered what this little field at the bottom of the app closing screen means. The English translation of the content would be "Arrival at work". If I touch it, Whatsapp opens. Can you guys tell me how this functionality is called and also the purpose of it?

This is a Siri feature, part of Siri's proactive abilities to suggest apps. This will suggest apps you may wish to use right now based on factors, one of which can be location. Siri has determined that you are likely to want to use this app in your current location, so it is suggested on the recent apps list at the bottom in your screenshot.