What is workflow step 100

I can see step 100 in Pending Actions but I do not see a step 100 workflow business rule set up. How is step 100 created?

Workflow Business Rules

Step 100 record is generated in Pending Actions when a transaction is released into workflow. 

Workflow step 100 is a record that the transaction was released into workflow. Once the transaction goes through all the steps to be approved, step 100 is automatically removed from Pending Actions.

The record can be used to notify the originator if the workflow is rejected.