It's a piece of code that's essentially an expiration date in the kernel for said flashcart device(s). The kernels are just DSTT clone kernels that overall feel clunky, two options to fix the issue, change the date of your system, or use YSMenu. The proper solution would be to buy a better flashcart running a good kernel, example, the R4i Gold 3DS Plus is a very good flashcart to get, it runs Wood R4 and doesn't have time bombs at all.
To make more money or to enforce you to upgrade the kernel, but just get a non-time bomb R4 card, we can have no worry about that, the R4i gold 3ds plus, Ace3ds Plus are what I know not with that. Have the first card in hand. It pretty works well.
While I know you mean in case of someone confusing schooling establishment from shooting establishment (many of the same letters) I am still going to read that as lockdown (also known as lock in) for a pub
being drunk in school was either because drunk on playing field or could not be arsed with one particular Thursday afternoon so went and had some beers and played some games instead before returning for an ill advised last lesson/period