Hi HN, I built an Android file viewer that opens PDF, Word, Excel, PowerPoint, images, video, audio, Markdown and code, and asks for no permissions at all. Gander holds no permissions, not even INTERNET so the OS itself guarantees the file cannot leave the phone. PDFs use Pdfium, media uses Media3, and Office formats are rendered by bundled JS libraries in a WebView and so no request goes to any server. It is a viewer only. Complex PowerPoint decks come out approximately right, spreadsheet charts are not drawn, and old binary .doc and .ppt are unsupported. It is 14 MB, MIT licensed and uploaded on GitHub releases.

The app receives files through the Storage Access Framework and "Open with" intents, so the OS hands it exactly the documents you chose and nothing else. Office formats render inside a locked-down WebView whose every request is intercepted by WebView Asset Loader: bundled JS libraries load from app assets and the documents stream from the content URI. No network stack is ever touched, and the app does not declare the INTERNET permission.

Supported formats include PDF, .docx, .xlsx, .pptx, images, video, audio, Markdown, and code. Legacy binary .doc and .ppt are not supported. Install via APK from GitHub releases or F-Droid (planned). Roadmap includes iOS companion and legacy format support if a usable offline renderer appears. Contributing welcome; a star helps others find it.