Unknown pipe in the garden and concrete cover

An acquaintance has set round point foundations for pavilions in his garden, which he regularly sets up for parties.
Anyone who doesn't know that might suspect who knows what behind it...

Why shouldn't the threaded pipe have functioned as a parasol stand?

The house was built in 1980, that was still a time when people generally improvised. If you wanted to set up a parasol, you didn't go to the hardware store and buy a special "parasol mounting pipe DN75"... if an acquaintance happened to have a 2" threaded pipe, it was just buried or driven in and that was that. The parasol fits in either way.

In short:
What the stuff really is for, you will only find out by consulting the spade and checking.

In winter, our neighbor always has a suitable pipe with a huge heavy birdhouse on top stuck in a concreted pipe embedded similarly deep as yours. It is so deep so that a storm cannot blow it over.

Here it helps to use some muscle power for exploration. Pressing the trigger on the phone probably is not sufficient.

If it were a well, the widow would probably know. A water supply would not go 2m vertically into the ground but only have the usual frost-proof foundation. Nobody knows what someone is thinking putting a water pipe more than 2m into the ground.

I would try to turn the pipe with an opinion amplifier AKA pipe wrench. Just throw away the concrete parts.

No matter what it is, it is probably not usable in a sensible way. I would thoroughly wet-mop a garden anyway, and on that occasion, I would tear both out as far as possible.

Short and sweet:
What that stuff really is, you'll only find out by consulting the spade and looking.

I'm not digging down >2m oO

I'll now test how deep it actually goes.

I'll try to pry up the concrete things to see if it's just a foundation or actually a cover for something.