Questions with the tag duplicate cover duplicate files, duplicate packages, duplicate lines and many more. Even if restricted to a specific usage, I can't think of any advantage of this tag, so I recommend to delete it.
This tag is ambiguous, but not useless. It conveys information which is relevant in searches. Please do not remove it without replacing it with a more precise tag.
Most uses seem to be about:
- Looking for identical or similar files → I just created duplicate-files
- Looking for duplicate lines or fields in a file (this should usually be used together with text-processing, but often isn't)