I tried to correct it here:
changeset/64622026
Please review.

Hi!
You created some ways without tags here, they looks like residential roads to me.
There are some roads with highway=track, did you use that because they are unpaved? If they are residential roads you should use surface=unpaved or similar to map that.
There is also one with highway=trackr
which is not yet connected to the road network.
way/645263966
Please try to correct this.

Hi! Why did you change a part of the track to highway=guessed_track?
Bing shows a way close to the way, so I wonder what to do.
way/645428209

Hi!
You use highway=barrier here, a very unusual tag. I think what you meant is a kerb? See kerb=*
One of the ways is here:
way/645143414

OK, seems I did not find the right words, so I've now corrected the other error:
changeset/64565746

Hi! I fixed typo highway=designated on
way/644339156
The ways next to it were highway=path and highway=cycleway. I think path fits best, so I changed it like that:
changeset/64554821

Möglicherweise lag es an JOSM, scheint eine total veraltete Version zu sein.

Moin! Was ist denn da schiefgegangen?
highway=3 + footway=Beton an einem Weg mit Länge 0?
way/644748882
An der gleichen Stelle ist dann auch noch ein zweiter Weg way/644748773

So far only for the first way. Did you find out what went wrong? I am just curious because there might be an error in JOSM. If so, it should be reported and fixed.

Oops, I just noticed that there is a second way on top of the other, so you have to download the area, not a single way.

If you download this way and run the validator JOSM should complain. If it doesn't you probably clicked on the Ignore button.
Try to remove the file validator\ignorederrors.

Any idea what went wrong? I guess you did not intend to produce these nodes.

Thanks for the feedback. There are still a few more:
http://overpass-turbo.eu/s/DGc

Yes, OK. Next time watch out for the typo.

The picture shows lamps on the sidewalk and lamps on the major road. Still, they are all rather normal lamps, so I would map them as nodes.

Hi! You changed highway=track to the unusual highway=unsurfaced here
way/146708704
Was that intended?

Hi! Please check way way/643894897
I think you wanted to draw two single nodes instead?
You should also add the tag lit=yes to the corresponding stretch of way/560468809

Hi! I've corrected the typo highway=sevice here:
changeset/64475173
DigitalGlobe Premium Imagery shows connections way/508120219
Why didn't you map it that way?

Hi! What does highway=model mean?
The bridge is tagged highway=raceway, so I guess this should be used for the whole way?
way/643888711

Oops, forgot a link:
way/643087705