What exactly is this doing?

[MRitter]

If ($(vDevelopment)=1,$1,Autonumberhash256($1))

What is the $1 doing in this load statement?

Thanks

[tresesco]

A bigger picture of your script could help understand that. It could be just a field name, it could be an argument passed to a function/sub-routine,...

[MRitter]

This is actually a variable(vKeyConverter)

The variable is then placed at the front of code that is building a key:

$(vKeyConverter([SNAPSHOT_ID]&
'$(vKeyDellimitter)'& [EMP_DK]&
'$(vKeyDellimitter)'& [DATA_MONTH_SK]&
'$(vKeyDellimitter)'& [TERR_NBR]&
'$(vKeyDellimitter)'& AutonumberHash256(GEOGRAPHY_ID_NM))) as [%KEY_SUMMARY_PAYOUT]