Find out since how long the cache has been stored in IndexDB?

I am using a web application for doing data entry which has a mechanism for storing the data entry form (which is an html form) in the browser cache IndexDB.
I am able to see the form in the browser dev tool like so : HTML form saved in IndexDB

I want to know for how long the Index DB will be able to store the form in the browser? Is it possible that it is months since the browser cache was same? Will closing the browser clear the keys? or is this persistent enough storage to last for a few months?

Is it possible to find out when(the exact date or time) the cache entry was made in the IndexDB?

I am asking this because I suspect some discperancy in the form for some of our users as the data being sent is a little different than expected.

Any help would is appreciated.

Thanks