The Externs tab is shown in the following figure.
Figure 1. Externs Tab
All externs found in the specified p4 file are displayed in this tab only for reference. There are four individual sub-sections, one per extern type. In each sub-section a table is displayed with some key configuration values, including instance name, width, type, etc.
Note: Checksum data width and Register latency are only displayed
after clicking the Calculate Latency button.