Hello,
I am new and I have simple question, but even after half an our search I did not find the answer here or anywhere else.
I have tagged some smaller streets with “name” using JOSM. This seemed to be the wrong key because someone changed it to “ref”. That is ok for me so far, but now I cannot see the street names in when I open https://www.openstreetmap.de/karte.html in Firefox. They are still there and I was able to see them when I used “name” but with “ref” they are gone.
Many thanks
It appears that people dont like you using names of streets which are not in the official register of streets: https://www.openstreetmap.org/changeset/54215568
To my mind this is completely wrong: OSM maps what can be verified on the ground, it is not the mouthpiece of any body. If the signs have Strasse 9 (sorry used to de-ch convention) on name plates and someone else visiting there can see them then they are appropriate for the name tag.
This person has changed your tags to loc_name which is not rendered. Loc name is not in general meant for ‘unofficial names’ but for names used by local people. So in a village near me the White Lion pub is known locally as Top House. However there may be an agreed convention for this within the German community (there is in France, so that even when signs say one thing the name tag uses the official name). In the UK we place official names where different from the usual name in official_name (not least because the official name of the country is very long).
The change was not justified at all. I commented on the changeset voicing my opposing opinion. I asked redrace to revert his changes. If he does not please do it yourself referencing to that changeset comment and this forum post. If you need help reverting report back here.
And by the way: Welcome to OSM. 
For German centric questions please also refer to the German forum on this board.
User redrace has reconsidered his opinion:
https://forum.openstreetmap.org/viewtopic.php?id=60777
A street sign is a valid source for the name tag.