Try "merge pdf", "crop image", "password", "read qr" or "15% of 80".

Format Lab

Technical notes on the file formats UNQIRO reads with its own parsers: how a format is built, why a file fails to open, and what you can check in your own file without uploading or running it.

How these pages are made

Every format here is one UNQIRO reads itself, in the browser. The byte maps and tables are produced by those readers from small example files when the pages are built, each page lists the specifications and sources it relies on, and each ends with a way to check your own file.

AppImage

How a Linux AppImage is built from an ELF runtime and a SquashFS image, where its icons live and which compression a reader must support.

ZIP

How a ZIP archive is read from its end, why one will not open, which compression and encryption a program must support, and where the real ZIP64 limits lie.