It seems that the details of the Pull Request are missing or undefined. Without specific information about the changes proposed in the Pull Request for the thanos-io/thanos project, I cannot generate a summary.

If you could provide more context or details about the specific changes, improvements, or issues addressed in the Pull Request, I would be happy to help create a summary tailored for an advanced developer. Please share any relevant information such as the files modified, new features introduced, bug fixes, or any related discussion points.