Every sector that holds data has this problem. These five are where solving it is worth the most.

Data is the common thread. A bank, a hospital, a training lab, a data controller and a defence programme all need to know what a model took from their data and why. Each calls the question something different, whether validation, audit, diagnosis, erasure or assurance, and each is told the same thing by their current stack. The answer cannot be recovered after training. It cannot. It has to be produced during it.

So these are not five products, five solutions or five versions of anything. They are five readings of one record, under one licence. What differs between them is the obligation driving the purchase, the person who signs, and how long the sale takes. Plenty of other sectors hold data under the same constraint and the same licence reaches them. These five are named because the cost of the missing account is already on somebody's books there, in figures that can be checked.