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EPUBCheck · Package and ZIP container

PKG-026

Updated:

EPUBCheck PKG-026 is an error message: “Obfuscated resource must be a Font Core Media Type (was declared as "…" in "…").” A file that is not a font is listed as obfuscated in META-INF/encryption.xml; font obfuscation only applies to font files.

The official message

Obfuscated resource must be a Font Core Media Type (was declared as "%1$s" in "%2$s").

Default severity
Error. The EPUB breaks a rule of the specification and is invalid. Stores and Send to Kindle may reject it, and EPUBCheck exits with status 1.
EPUBCheck version
5.4.0

%1$s, %2$s… are filled in with the file, value or element EPUBCheck found.

Typical causes

  • An encryption.xml copied from another book that lists files this book does not use as fonts.
  • A tool that obfuscated every resource instead of only the fonts.

How to fix it

  • Remove the entry for the non-font file from META-INF/encryption.xml and store that file unobfuscated.

Terms used here

Other PKG messages

  • PKG-025 Publication resource must not be located in the META-INF directory
  • PKG-027 Could not extract EPUB ZIP content, probably due to file names not encoded in UTF-8.
  • PKG-024 Uncommon EPUB file extension.
  • PKG-022 Wrong file extension for image. The image is a "…" file but has the file extension "…".
  • PKG-021 Corrupted image file encountered.
  • PKG-017 Uncommon EPUB file extension.

Message text and severity from EPUBCheck 5.4.0 (W3C, BSD-3-Clause). Explanation by EPUBLab.

FAQ

What does EPUBCheck PKG-026 mean?

EPUBCheck PKG-026 is an error message: “Obfuscated resource must be a Font Core Media Type (was declared as "…" in "…").” A file that is not a font is listed as obfuscated in META-INF/encryption.xml; font obfuscation only applies to font files.

Is PKG-026 an error?

PKG-026 is reported as error by default. The EPUB breaks a rule of the specification and is invalid. Stores and Send to Kindle may reject it, and EPUBCheck exits with status 1.