/usr/share/php/kohana3.1/system/utf8/ is in libkohana3.1-core-php 3.1.5-1.1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/php/kohana3.1/system/utf8/from_unicode.php
/usr/share/php/kohana3.1/system/utf8/ltrim.php
/usr/share/php/kohana3.1/system/utf8/ord.php
/usr/share/php/kohana3.1/system/utf8/rtrim.php
/usr/share/php/kohana3.1/system/utf8/str_ireplace.php
/usr/share/php/kohana3.1/system/utf8/str_pad.php
/usr/share/php/kohana3.1/system/utf8/str_split.php
/usr/share/php/kohana3.1/system/utf8/strcasecmp.php
/usr/share/php/kohana3.1/system/utf8/strcspn.php
/usr/share/php/kohana3.1/system/utf8/stristr.php
/usr/share/php/kohana3.1/system/utf8/strlen.php
/usr/share/php/kohana3.1/system/utf8/strpos.php
/usr/share/php/kohana3.1/system/utf8/strrev.php
/usr/share/php/kohana3.1/system/utf8/strrpos.php
/usr/share/php/kohana3.1/system/utf8/strspn.php
/usr/share/php/kohana3.1/system/utf8/strtolower.php
/usr/share/php/kohana3.1/system/utf8/strtoupper.php
/usr/share/php/kohana3.1/system/utf8/substr.php
/usr/share/php/kohana3.1/system/utf8/substr_replace.php
/usr/share/php/kohana3.1/system/utf8/to_unicode.php
/usr/share/php/kohana3.1/system/utf8/transliterate_to_ascii.php
/usr/share/php/kohana3.1/system/utf8/trim.php
/usr/share/php/kohana3.1/system/utf8/ucfirst.php
/usr/share/php/kohana3.1/system/utf8/ucwords.php