Can someone explain how to use the ".since" pragma?

[mrhdias]

In the following example, does it mean that the procedure with the pragma 
".since" will be used starting with Nim 1.1? 
    
    
    include "system/inclrtl"
    
    proc test() =
      echo "old test"
    
    proc test() {.since: (1, 1).} =
      echo "new test"
    
    test()
    
    
    Run

Where can I find documentation about this pragma?