Why can the second parameter ``formdata.append () `wear through the object?

scene: the image information obtained through the camera is the data containing rui . To upload the file, the code to Baidu is:

What you see in 
  document  is: 


 formData.append (name, value, filename) 
 value 
 The field"s value. This can be a USVString or Blob (including 
 subclasses such as File). 



The 
 document mentions that the parameter is  USVString  or  Blob , so why can you use an object that contains file information instead?
Upload file formdata
Mar.04,2021

you can print that file, is actually a js object 

console.log(document.querySelector('input[type=file]').files[0])

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MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1bedee1-46149.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1bedee1-46149.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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