What is DBCC66 and DBCC63 files Tried to get some clarity but can't find any thing googling or searching  in forums.  

We got a couple of files in the Data folder of one of our MS SQL servers

databasename.ndf_MSSQL_DBCC66
databasename.ndf_MSSQL_DBCC63

Can anyone tell me what these files are?
These are the sparse files checkdb makes while running: https://blogs.msdn.microsoft.com/jorgepc/2010/11/25/what-are-sparse-files-and-why-should-i-care-as-sql-server-dba/