This woud be wery useful in walltablets etc.
I asked the creator of Fully Kiosk Browser to add idle time on MQTT and JavaScript API, as he already tracks it for the internal Idle Page Reload feature.
He said, that he might add it with the upcoming 1.57 release.
My idea was also to use it in combination with browser-mod to return to the default dashboard.
Will only help you in case your‘re using Fully, but maybe that information might be helpful for you …
At the moment I´m already using FKB, but I´d like to drop it off and change my wall tablet to mini PC with touch screen instead. So even if this might help a lot of people, it would not solve my case. But thanks for the info and effort!