/usr/lib/ruby/vendor_ruby/pdf/reader/afm/ is in ruby-pdf-reader 1.3.3-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/Courier-Bold.afm
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/Courier-BoldOblique.afm
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/Courier-Oblique.afm
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/Courier.afm
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/Helvetica-Bold.afm
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/Helvetica-BoldOblique.afm
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/Helvetica-Oblique.afm
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/Helvetica.afm
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/Symbol.afm
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/Times-Bold.afm
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/Times-BoldItalic.afm
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/Times-Italic.afm
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/Times-Roman.afm
/usr/lib/ruby/vendor_ruby/pdf/reader/afm/ZapfDingbats.afm