April 2026 Monthly Summary for prometheus/prometheus: Focused on expanding Prometheus tooling capabilities with parity enhancements and improved multi-tenant support. Key deliverable: added the --header flag to promtool query instant to mirror the existing query range behavior, enabling users to send custom HTTP headers (e.g., X-Scope-OrgID) without relying on an http.config.file. This reduces configuration overhead, enhances security posture in multi-tenant environments, and streamlines automation in CI/CD pipelines. There were no major bugs fixed this month; the effort emphasized feature parity, reliability, and developer productivity. Overall impact: smoother operator experience, faster onboarding, and better alignment with Prometheus ecosystem tooling.