How to determine a file type without an extension or with an incorrect extension?

How to to determine determine a a file file type type without without an an extension extension or or with with an an incorrect incorrect extension?

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How to determine a file type without an extension or with an incorrect extension?
Source
How to determine a file type without an extension or with an incorrect extension? - Program, Hyde, Innovations, Technologies, Windows, Telegram (link)
How to determine a file type without an extension or with an incorrect extension? - Program, Hyde, Innovations, Technologies, Windows, Telegram (link)
Telegram (link) Windows Hyde Innovations Program Technologies
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