/usr/share/iceowl/extensions/langpack-es-ar@lightning.debian.org/chrome.manifest is in lightning-l10n-es-ar 1:45.8.0-3~deb8u1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | locale calendar es-AR jar:chrome/es-AR.jar!/locale/es-AR/calendar/
locale lightning es-AR jar:chrome/es-AR.jar!/locale/es-AR/lightning/
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