/usr/share/xml/docbook/custom/website/2.5.0/schema/relaxng/ is in docbook-website 2.5.0.0-8.
This file is owned by root:root, with mode 0o755.
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/usr/share/xml/docbook/custom/website/2.5.0/schema/relaxng/ChangeLog
/usr/share/xml/docbook/custom/website/2.5.0/schema/relaxng/autolayout.rng
/usr/share/xml/docbook/custom/website/2.5.0/schema/relaxng/config.xml
/usr/share/xml/docbook/custom/website/2.5.0/schema/relaxng/extensions.rng
/usr/share/xml/docbook/custom/website/2.5.0/schema/relaxng/forms.rng
/usr/share/xml/docbook/custom/website/2.5.0/schema/relaxng/layout.rng
/usr/share/xml/docbook/custom/website/2.5.0/schema/relaxng/rddl.rng
/usr/share/xml/docbook/custom/website/2.5.0/schema/relaxng/union.xml
/usr/share/xml/docbook/custom/website/2.5.0/schema/relaxng/website-full.rng
/usr/share/xml/docbook/custom/website/2.5.0/schema/relaxng/website.rng
/usr/share/xml/docbook/custom/website/2.5.0/schema/relaxng/websitedb.rng