The Jitterbit Harmony system defines certain global variables that are always available throughout your project, known as Jitterbit variables or as predefined global variables. Jitterbit variables are predefined by Jitterbit or set in the Jitterbit configuration file.
The most common use case for Jitterbit variables is to read a variable so that you can gather information about what occurred during an operation or to fetch global information such as the name of the current source file. Another common use case is to use Jitterbit variables to change default settings used for processing the operation chain.
Refer to these pages for documentation on the predefined Jitterbit variables: