Never ever???
Checksum
MD5 (Message Digest Method 5) is a cryptographic hash algorithm used to generate a 128-bit digest from a string of any length. It represents the digests as 32 digit hexadecimal numbers. Ronald Rivest designed this algorithm in 1991 to provide the means for digital signature verification
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That's happens when the content is copied directly without checking

You can delete all md5 files