...
When using coefficient set functions, the value elements can contain tags between "@" signs (e.g. "@NUMBER@") that refer to location attributes that are defined in the locationSets configuration file. The tags are replaced by actual values. These values can be different for different locations and time periods. See 22 Locations and attributes defined in Shape-DBF files for more information.
...
The example below uses coefficientSetFunctions (available since build 30246). Here 'X' is a reference to a variable and 'a', 'b' and 'c' are references to coefficients. Here the coefficients are defined in coefficientSetFunctions, where @coef_a@, @coef_b@ and @coef_c@ refer to location number attributes that are defined in the locationSets configuration file.
...