good morning and happy new year!
Help me: I remember a setting where it was possible to select a certain time to keep that device or entity in that area or not (like at home).
I don’t remember if that setting was inside HA or inside the application on the iPhone
For example: consider home after 30 seconds.
Thanks
It is part of device teacker options. Integrations providing device trackers may or may not allow you to set it. Those configured in yaml should:
The ping integration also used to have it, but it was removed.
yes.
I remember that there was an option in settings that you could set the time…
without acting directly on the yaml configuration 
(Based on GPS)
That would totally depend on what integration provided it. That is anyones guess.