/usr/share/doc/ruby-rubymail-doc/html/files/lib/rmail/ is in ruby-rubymail-doc 1.0.0-2.
This file is owned by root:root, with mode 0o755.
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/usr/share/doc/ruby-rubymail-doc/html/files/lib/rmail/address_rb.html
/usr/share/doc/ruby-rubymail-doc/html/files/lib/rmail/header_rb.html
/usr/share/doc/ruby-rubymail-doc/html/files/lib/rmail/mailbox/
/usr/share/doc/ruby-rubymail-doc/html/files/lib/rmail/mailbox/mboxreader_rb.html
/usr/share/doc/ruby-rubymail-doc/html/files/lib/rmail/mailbox_rb.html
/usr/share/doc/ruby-rubymail-doc/html/files/lib/rmail/message_rb.html
/usr/share/doc/ruby-rubymail-doc/html/files/lib/rmail/parser/
/usr/share/doc/ruby-rubymail-doc/html/files/lib/rmail/parser/multipart_rb.html
/usr/share/doc/ruby-rubymail-doc/html/files/lib/rmail/parser/pushbackreader_rb.html
/usr/share/doc/ruby-rubymail-doc/html/files/lib/rmail/parser_rb.html
/usr/share/doc/ruby-rubymail-doc/html/files/lib/rmail/serialize_rb.html
/usr/share/doc/ruby-rubymail-doc/html/files/lib/rmail/utils_rb.html