Hello experts in this tread! 
Thanks for the knowledge.
I opened a new question How to limit allowed characters in file and directory names?
– “How to limit allowed characters in file and directory names?” – but related to the problem discussed here: “Why does Nextcloud restrict characters in directory names?”
And in the new tread I’m pointing to your posts.
Hope using the screenshots in new question from you is ok!?
User https://help.nextcloud.com/u/j-ed showed us under Windows:
User: https://help.nextcloud.com/u/rakekniven made that with Mac OS:
It would be nice if you have an idea, to “How to limit allowed characters in file and directory names?”
And may can answer in the new thread?
Thank you very much.