In the Google Search Console report "Duplicate without user-selected canonical", how do you find the duplicate URL of a particular URL? Going into "Inspect URL" doesn't seem to identify the location of the other (duplicate) file. I can find the duplicate only when the "Google-selected canonical" selects the other URL, but that doesn't always happen.
To find the source of the duplicate, you could Google a large part of the page content to find out wich page(s) are indexed with this particular content.
For a better result, you should put your query into brackets.
Plz provide more details (url for example) for a more detailed answer.
Clear Answer: There is no way to find its easily.
You can just use external tools for detecting duplicate contents without 100% exact result or you can try it manually.