A lot of people talking about the details, does not constitute official documentation though. You can find a lot of articles talking about SQL Server's DBCC IN

A lot of people talking about the details, does not constitute official documentation though. You can find a lot of articles talking about SQL Server's DBCC IND and DBCC PAGE, but that isn't official documentation – they are essentially internal functions and not supported and could change or go away entirely despite having been around for many versions, as they have in Azure). Similarly there articles talking about sys.dm_db_database_page_allocations which sort-of does the job of DBCC IND, but again this is not officially documented & supported. > I am uncertain what you mean by "external interface". I meant the published interface. Maybe "supported API" would have been a better phrase to use? Though as pointed out below, there is at least some official documentation on the MFT structure.