Caveat emptor
let the buyer beware
Where the phrase comes from
A sale maxim from the older common law. The buyer who could inspect was expected to inspect. Modern consumer statutes, implied terms, and disclosure rules have cut the maxim down.
What lawyers are pointing at
The history matters because people still quote the Latin as if it were the whole law. In a private sale of a specific used thing, inspection still does real work. In a consumer sale, merchantability, fitness, and bans on misleading conduct often put the risk of a hidden defect on the seller. Quoting caveat emptor in a checkout does not cancel those statutes. It is a description of an older allocation of risk, not a shield.
The same shape in code
An unmarked dependency, a library with no tests, and a binary blob ask the integrator to beware. That is a fair warning only if you actually say what you did not test. Hiding the gap and then pointing at the maxim is the software version of a seller who covered the crack in the beam.
A concrete picture
A person buys a second-hand chair at a private garage sale and does not sit in it. The older maxim put that look-and-try on the buyer. A shop selling the same chair as new is in a different legal world.