/usr/share/ubiquity-slideshow/slides/l10n/pt/ is in ubiquity-slideshow-xubuntu 83.
This file is owned by root:root, with mode 0o755.
..
/usr/share/ubiquity-slideshow/slides/l10n/pt/00_welcome.html
/usr/share/ubiquity-slideshow/slides/l10n/pt/01_desktop.html
/usr/share/ubiquity-slideshow/slides/l10n/pt/02_whiskermenu.html
/usr/share/ubiquity-slideshow/slides/l10n/pt/03_personalize.html
/usr/share/ubiquity-slideshow/slides/l10n/pt/04_customize.html
/usr/share/ubiquity-slideshow/slides/l10n/pt/05_defaultapps.html
/usr/share/ubiquity-slideshow/slides/l10n/pt/06_support.html
/usr/share/ubiquity-slideshow/slides/l10n/pt/07_thanks.html
/usr/share/ubiquity-slideshow/slides/l10n/pt_BR/00_welcome.html
/usr/share/ubiquity-slideshow/slides/l10n/pt_BR/01_desktop.html
/usr/share/ubiquity-slideshow/slides/l10n/pt_BR/02_whiskermenu.html
/usr/share/ubiquity-slideshow/slides/l10n/pt_BR/03_personalize.html
/usr/share/ubiquity-slideshow/slides/l10n/pt_BR/04_customize.html
/usr/share/ubiquity-slideshow/slides/l10n/pt_BR/05_defaultapps.html
/usr/share/ubiquity-slideshow/slides/l10n/pt_BR/06_support.html
/usr/share/ubiquity-slideshow/slides/l10n/pt_BR/07_thanks.html