A GS1 Application Identifier (Global) is a 2, 3 or 4 digit code, that indicates the meaning (or status) of the data, which immediately follows the GS1 Application Identifier (Global).

A GS1 Application Identifier (Global) identifies the type of data used for the purposes of Automatic Identification and Data Capture using GS1 standards.

For further guidance see the GS1 website at: GS1 General Specifications.