Gander: A 14 MB Android file viewer that requests zero permissions

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A developer has released Gander, a free and open-source Android app that can open PDFs, Office documents, images, video, audio, Markdown, and code files without requesting any device permissions. Because the app is denied even internet access, the operating system itself ensures no file data can be transmitted off the device. Most existing Android file viewers either come bundled in large office suites requiring sign-in or are lightweight apps that upload files to remote servers for rendering. Gander handles all processing locally using Pdfium for PDFs, Media3 for media, and bundled JavaScript libraries in a WebView for Office formats. The app weighs 14 MB, is MIT licensed, and is available on GitHub, though it currently lacks support for old binary .doc and .ppt formats and does not render spreadsheet charts.

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