It does indeed. It should also be possible to write a function that reads its own return address from the stack and then returns this value as the result. This then could be passed to GetLocationInfo. I'm not sure how to implement this, but it shouldn't be rocket science.
Edit: There is System.ReturnAddress, introduced with Delphi XE2, which gives you just that, so
function GetCurrentLineNumber: Integer;
var
ModInfo: TJclLocationInfo;
begin
ModInfo := GetLocationInfo(ReturnAddress);
Result := ModInfo.LineNumber;
end;
Should do the trick (untested)
Edit: Just tried it. It works, at least in Delphi 10.2.
Edit: JclDebug already contains such a function called LineByLevel.