Worked on targeted maintenance and quality improvements across AdguardTeam/KnowledgeBaseDNS and AdguardTeam/AdguardFilters repositories, focusing on documentation accuracy and filter list management. Addressed documentation inconsistencies by correcting IPv6 CIDR notation in the Disallowed Clients section using Markdown and text editing, ensuring the knowledge base accurately reflected network behavior and reduced user confusion. In AdguardFilters, resolved a stealth mode issue affecting thuedientu.gdt.gov.vn by updating allowlist_stealth.txt, isolating the fix to minimize impact on unrelated domains. Demonstrated disciplined version control and clear issue tracking, emphasizing operational clarity and maintainability. No new features were introduced, with efforts concentrated on bug fixes and documentation.