/usr/share/squirrelmail/functions/decode/ is in squirrelmail-decode 1.2-1.
This file is owned by root:root, with mode 0o755.
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/usr/share/squirrelmail/functions/decode/big5.php
/usr/share/squirrelmail/functions/decode/cp874.php
/usr/share/squirrelmail/functions/decode/cp949.php
/usr/share/squirrelmail/functions/decode/euc_cn.php
/usr/share/squirrelmail/functions/decode/euc_jp.php
/usr/share/squirrelmail/functions/decode/euc_kr.php
/usr/share/squirrelmail/functions/decode/euc_tw.php
/usr/share/squirrelmail/functions/decode/gb18030.php
/usr/share/squirrelmail/functions/decode/gb2312.php
/usr/share/squirrelmail/functions/decode/iso_2022_cn.php
/usr/share/squirrelmail/functions/decode/iso_2022_jp.php
/usr/share/squirrelmail/functions/decode/iso_2022_jp_2.php
/usr/share/squirrelmail/functions/decode/iso_2022_kr.php
/usr/share/squirrelmail/functions/decode/iso_2022_support.php
/usr/share/squirrelmail/functions/decode/shift_jis.php
/usr/share/squirrelmail/functions/decode/x_mac_arabic.php
/usr/share/squirrelmail/functions/decode/x_mac_ce.php
/usr/share/squirrelmail/functions/decode/x_mac_chinsimp.php
/usr/share/squirrelmail/functions/decode/x_mac_chintrad.php
/usr/share/squirrelmail/functions/decode/x_mac_croatian.php
/usr/share/squirrelmail/functions/decode/x_mac_cyrillic.php
/usr/share/squirrelmail/functions/decode/x_mac_devanagari.php
/usr/share/squirrelmail/functions/decode/x_mac_farsi.php
/usr/share/squirrelmail/functions/decode/x_mac_greek.php
/usr/share/squirrelmail/functions/decode/x_mac_gujarati.php
/usr/share/squirrelmail/functions/decode/x_mac_gurmukhi.php
/usr/share/squirrelmail/functions/decode/x_mac_hebrew.php
/usr/share/squirrelmail/functions/decode/x_mac_icelandic.php
/usr/share/squirrelmail/functions/decode/x_mac_roman.php
/usr/share/squirrelmail/functions/decode/x_mac_romanian.php
/usr/share/squirrelmail/functions/decode/x_mac_thai.php
/usr/share/squirrelmail/functions/decode/x_mac_turkish.php
/usr/share/squirrelmail/functions/decode/x_mac_ukrainian.php