/usr/share/xml/docbook/custom/slides/3.4.0/schema/ is in docbook-slides 3.4.0-5.
This file is owned by root:root, with mode 0o755.
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/usr/share/xml/docbook/custom/slides/3.4.0/schema/ChangeLog
/usr/share/xml/docbook/custom/slides/3.4.0/schema/dtd/
/usr/share/xml/docbook/custom/slides/3.4.0/schema/dtd/ChangeLog
/usr/share/xml/docbook/custom/slides/3.4.0/schema/dtd/catalog
/usr/share/xml/docbook/custom/slides/3.4.0/schema/dtd/slides-custom.dtd
/usr/share/xml/docbook/custom/slides/3.4.0/schema/dtd/slides-full.dtd
/usr/share/xml/docbook/custom/slides/3.4.0/schema/dtd/slides.dtd
/usr/share/xml/docbook/custom/slides/3.4.0/schema/dtd/slides.mod
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/ChangeLog
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/calstblx.rnc
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/calstblx.rng
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/dbhierx.mod.rnc
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/dbhierx.mod.rng
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/dbnotnx.mod.rnc
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/dbnotnx.mod.rng
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/dbpoolx.mod.rnc
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/dbpoolx.mod.rng
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/docbookx.rnc
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/docbookx.rng
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/htmltblx.mod.rnc
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/htmltblx.mod.rng
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/slides-full.rnc
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/slides-full.rng
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/slides.mod.rnc
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/slides.mod.rng
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/slides.rnc
/usr/share/xml/docbook/custom/slides/3.4.0/schema/relaxng/slides.rng