Non-ASCII in URLs

Greetings,

I am trying to figure out what the normative rules are for Non-ASCII characters in URLs in Hugo.

For instance I am using the Academic Theme and I can create a new .md file manually (projects) with the name U̱t-Ma’in noun research.md or U̱t-Ma’in-noun-research.md

in each case the saltillo U+A78C causes hugo to not compile so it just hangs.

$ hugo new project/U̱t-Ma’in-noun-research.md
>

But the following works:

hugo new project/U̱t-Main-noun-research.md

I’ve read the following but it doesn’t clearly answer my question