Thanks for all the comments! I will release the code as a module. Except that I already know that I'm bad at naming things. My current favourite is to name the routine clean_fragment() (instead of sanitize_name from above), and the module Text::CleanFragment. I've rejected Text::ASCIIfy or something including ASCII, because whitespace and / are part of ASCII but would be unsafe to use in the result.

A better name would imply that the results are good to use as filenames or URL fragments.