Just to point, but shifting left isn't agile at all. In fact, it's slightly against development agility.

It's just a good engineering practice, that is more than useful enough to compensate for any loss of agility it may cause.

On the one hand, I agree.

On the other hand, like a lot of other good ideas, the agile community has claimed this. A quick google will show that many claim it is a "core agile idea."