Comprehensive guidelines for Obsidian.md plugin development including all 27 ESLint rules from eslint-plugin-obsidianmd v0.1.9, TypeScript best practices, memory management, API usage (requestUrl vs fetch), UI/UX standards, locale file sentence-case enforcement, and submission requirements. Use when working with Obsidian plugins, main.ts files, manifest.json, Plugin class, MarkdownView, TFile, vault operations, or any Obsidian API development.