Clarification needed on the meaning of "Ose" in step-related code

<img width="593" alt="Image" src="https://github.com/user-attachments/assets/fab071a4-ae0f-491b-9764-bcbe7f0e29a0" />
I'm exploring the codebase and noticed the term "Ose" used in the context of steps 
1、Is "Ose" an abbreviation? If so, what does it stand for?
2、What's its intended role in the step logic?
This would help me better understand the architecture. Thanks for your time!

