The history had a name, it's my registered user which didn't have a public name (in the URL, the part between the /u/ and the /h/ is empty).
Ahh, I see. Yes, this needs to be fixed (in the form of a warning or documentation).
I think we can address these issues. You are right however that it *is* now possible for a user to change the url to a history. This is deliberate. There are a number of problems with the ID hashing approach we were using, primarily that ID stability relies of a secret key.
I actually liked the hashed-id very much... it was stable and reproducible, and supposedly safe (assuming the galaxy admin replaced the "changethisinproductiontoo" in the INI file). You're still going to use hashed-id for public datasets and workflows, aren't you?
We're trying to remove reliance on hashed ids where possible. For workflows this has already been changed. (Old identifiers will continue to work).