In short Execution Entry Point is a type of sequence. There are 5 types:
Execution Entry Point
Configuration Entry Point
Model Callback
Engine Callback
Normal
They are red in color and can only exist in process models.
Here is from the TestStand help:
https://www.ni.com/docs/en-US/bundle/teststand/page/using-execution-entry-points.html
Hope this helps,
