It seems that the Pull Request you mentioned is undefined or lacks specific details. Without additional context or information regarding the changes, improvements, or issues addressed in the pull request for the Thanos project (thanos-io/thanos), I am unable to provide a comprehensive summary.

To create a useful summary for an advanced developer, you would typically include key information such as:

1. Purpose: What is the objective of the changes? Are they adding a feature, fixing a bug, or enhancing performance?
2. Key Changes: A high-level overview of the main modifications or additions made in the code.
3. Impact: How will these changes affect the existing codebase, and what are the implications for users?
4. Implementation Details: Any specific technical choices or patterns used that might be relevant for a developer to understand the context of the changes.
5. Testing: Information about any tests added or modified, and how they confirm the changes work as intended.

If you provide more details about the pull request or its objectives, I would be glad to help you craft a specific summary!