Here, you can create, update or delete Global Parameters.
Global Parameter is a name/value pair. Once defined, you can use the name in a directive parameter field and it will be replaced in the final rule by the value for that name.
The syntax to use a parameter is ${rudder.param.<key>}, where <key> is the name you chose for your Global Parameter.
Be careful to enter exactly rudder.param (lower case) and your parameter name with the same case (Global Parameter keys are case sensitive).