The questions do actually vary. There are the three 'standard' questions which used to be asked everywhere. They are no longer asked at every airport, and certainly not for every flight.

Then there are the additional, random, often bizarre questions. One is asked these before one can even check in for a US carrier, US bound flight (at LHR, MUC and FRA for example the questioner is before the check in area for UA). Then one may be asked additional questions before entering the gate area. (I was asked those exactly once, at MUC)

The questions as some have stated are asked by airline employees or security contractors. They are sometimes truly bizarre. What does annoy me is that the ones at MUC and FRA often do not speak German, and only speak heavily accented English. That is just useless is doing much at all to act as a deterrent or to scope out possible troublemakers. I tell them every single time that they should ask me in German, and sometimes they give up. I also cannot understand some of the American accents or terminology even at this point in my life and thus cannot answer some of the questions.

But I wouldn't think that this mandated, European model in use for some flights is what is being discussed here.

And I still question if like 'pronounce your name' and 'spell your name' the TSA is prepared to handle those passengers who do not speak English.