The Convert.ToBoolean method converts a specified value to a Boolean value, which can be either True or False. The method can accept different types of values, such as numbers, strings, objects, etc. However, the conversion rules depend on the type of the value. For numbers, the conversion rule is as follows1:

If the value is zero, the method returns False.

If the value is non-zero, the method returns True.

Therefore, if the IntVar variable is an Int32 variable with the value 0, the expression Convert.ToBoolean(IntVar) will return False. The Log Message activity will display the value False in the Output panel after the execution. References: Convert.ToBoolean Method from UiPath documentation.