The key component of SPAN parameter files is a Risk Array. They consist of an array of potential losses per lot based on each of  the 16 SPAN scenarios.  The rest of the SPAN parameter file consists of all the other data needed to replicate the margin calculation, for example the Intercommodity Offsets allowed between different contracts.

The Risk Array concept is also used in the data provided by CCPs for replicating VaR based ETD margin algorithms; it’s just that they are a lot bigger – based on the number of VaR scenarios.