Income Tax provision – what is this?

Hello!
Can some kind person explain to a stupid Nomad what the hell “Income tax provision” means?

I’ve realised that it is not the sum of taxes accrued in IS for the current year.

Why “over provision” is shown on Credit in a trial balance. Where does it comes from? From previous year? Where it was a year ago then? In SFP?

What could it be…? Who knows?