What does a "computer move" mean?

qd5 is very hard to understand

Qd5 is a blunder...there's no point in showing a computer set on "easy".  What happened here is that black is in check, and the "easy" mode of this chess engine is programmed to randomly select a move that is not the best, but perhaps 3rd or 4th best.  In this case, it being check, there are not a lot of options at all and the computer randomly "blunders" by not going with the top move.

This is how/why "easy" modes on computers do not play like humans that are low rated, they just play weird moves.  Good chess software would have a more robust way of choosing non-optimal moves to simulate a weaker player.  If you've ever seen a computer on a weak setting suddenly sac a knight or bishop for a pawn with no plan or compensation, then you have seen this phenom in action.

I saw it while making my 4. d3 repertoire, so it took 2 minutes to find the book and find the right page. I'm sure you can find similiar computer moves in some variations of the Grunfeld, Traxler Counter-Attack and Kings Indian. And semi-slav, obviously.

I think there are three main types of computer moves people speak of.  The first are dumb only moves to avoid resigning.  If you are threatening mate in one and there is no defense, the computer will start sacking pieces to make it mate in two or three.  Humans don't normally do that.

Second are moves that violate rules or principles or have no obvious benefit other than they work tactically at a level that humans generally cannot calculate.

The final type are moves that follow general rules when it is an obvious exception.  There are some programs with limits that mean it cannot see certain plans that appear obvious to humans in a few unique situations.

The first type you will see a lot of in tactics trainer.  When the computer starts throwing everything at you, you know you made a good move.  The second is what people try to avoid by limiting the use of engines in their anaylsis.  There is no point in getting advice you cannot use or learn from.  While you can get benefit from some computer suggestions, there are others that while winning, are of a nature that you cannot learn from them.  The final type was or is used to develop strategies to beat computers.