How are header anchors generated in markdown containing non-ascii characters?

Using Streamlit
1

I am loading a markdown file to be displayed in my streamlit app. Some of the headers contain special characters like ä, ö, ü, ß, etc. Whener that is the case, the generated anchor is just an id, and not the hyphenated words of the header. In order to link correctly to the header, I need to use the same logic. However, I could not find how these ids are genreated?

A similar question was also asked here, however, without resolution: Long Anchor Tag Generation