As an example, for the Juniper JUNOS Device Family, you will see the following for the "Change Event Source" parameter:
<Please see attached file for image>

The purpose of this table is when the trap is received, the "Source" value sent with the trap is a numeric value. This table maps the numeric value to a text value in the event. So instead of see the number "2" in the event, you would see the text "cli". Values can be changed or added as needed.
For example, to change "1:other" to "1:OTHER":
1. Highlight "1:other" in the list and click on
Remove button
2. Click on
Add and enter "1:OTHER" in the "Source index entry" field and then click the OK button
To add a new value, click on
Add and enter the (entry #):(text) and then click on the OK button