.opf file: how to open it on Windows

5 Windows apps register the .opf extension. Install one of them to open the file with a double-click.

About the format

Format

Obsidium Project File

PRONOM identifier

fmt/207, fmt/2032

Format data: freedesktop.org shared-mime-info and PRONOM (The National Archives, UK).

• 
  calibre

  calibre is the one stop solution to all your e-book needs.

  Open source 9.17.0 1.5M ↓ ★ 26.2K
• 
  Kindle Previewer

  Preview your eBook before you publish it

  Free 3.107.0 7.8K ↓
• 
  PageEdit

  An ePub visual XHTML editor based on Sigil's Deprecated BookView. It uses WebEngine instead of WebKit.

  Open source 2.7.6 ★ 310
• S
  Sublime Text 4

  Sublime is a sophisticated cross-platform text editor for code, markup and prose.

  Proprietary 4.0.0.421500
• P
  Pix4Dmatic

  Next generation photogrammetry software for professional drone and terrestrial mapping

  Proprietary 1.86.0

Related guide: Change the default app for a file type in Windows