It’s just a quick and easy fitting free way to fill a hole like that. You cut the hole to square then cut a plug from a larger piece of board - but with the backing paper larger than the plug. You then bond it in with filler or whatever. It’s nice because You can get a really flat finish without needing to be very accurate or dick around with filler and you aren’t messing about around with wood and screws.
It’s just a quick and easy fitting free way to fill a hole like that. You cut the hole to square then cut a plug from a larger piece of board - but with the backing paper larger than the plug. You then bond it in with filler or whatever. It’s nice because You can get a really flat finish without needing to be very accurate or dick around with filler and you aren’t messing about around with wood and screws.