Description:
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PHP Version is 7.1.23 but the drop down wouldn't let me select it. Version 7.1.23 is the version that's in the repository for RedHat 7 so I think it's still relevant.

To reproduce:
1) Create a text file that has content starting with "HK".
2) Use the PHP function "mime_content_type" to display the mime type.
3) The function incorrectly reports "application/zlib".

Test script:
---------------
<?php

var_dump(mime_content_type("file.txt"));

?>

Expected result:
----------------
application/zlib is reported instead of text/plain.