Ref:
https://community.bistudio.com/wiki/Description.ext#Mission_parameters
https://community.bistudio.com/wiki/STEAMWORKSquery#Main_Table
https://community.bistudio.com/wiki/BIS_fnc_getParamValue
Reasoning:
param1 and param2 are transfer via Steam protocol. To be able to adjust them dynamically in a mission or via mods via sqf would give great flexibility to transmit custom data to external services or a server browser.
Syntax:
paramClass setParameter value;
Note:
Valid values for paramClass would be only param1 and param2 (string).