What is considered as a narrow road? Definition?

[EN] Hello, what are the keys/values/attributes which define a “narrow road” in Kurviger? In the documentation (There was an issue during the route calculation or navigation, what can I do about it? [Kurviger Knowledgebase]) nothing specific is mentioned.
(I’m actively mapping on OSM, and therefore it would help me to know what to look for when I’m mapping. Or simply understanding the reasoning of the Kurviger routing. For example, is it a narrow road when highway=track, or lanes=1, or when width=* is below a certain value?)

[DE] Hallo, welche Attribute/Merkmale kennzeichnen eine “kleinste Straße” in Kurviger? Was wurde hier festgelegt, wo finde ich das? In der Documentation (There was an issue during the route calculation or navigation, what can I do about it? [Kurviger Knowledgebase]) ist nichts genaues erwähnt.

The recognition of narrow roads is mostly done based on the highway class so a highway=track will be marked as narrow. Unfortunately, lanes and width don’t work well because they are used very inconsistently by different mappers.

Dear boldtrn,
I see, good to know. Thank you for your reply!
Best regards,