MD5 Checksum File
A checksum is a data usually fixed in size that is used to check if files have been changed and through this check the Integrity of the data. This is usually used for downloaded files but is also used for discs and disc images.
MD5 is the extension used for .md5 checksums, these are usually 32 characters long.
How to open .md5 files?
Software to open .md5 files
What are .md5 files