/usr/share/ucto/smiley.rule is in libucto2 0.9.6-1build2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | SMILEY=^(?:[oO>}\])]?)(?:[\:;8][',]?[-\^]?(?:[sSdDpPcCoO#@*$|?]|\)\)*|\{|\[|\(\(*)=?)$
REVERSE-SMILEY=^(?:\(|\)|\}*)(?:[sScCoO#@*$|?]?|\{|\[|\(\(?)=?(?:[',]?[-\^]?[\:;8])(?:[oO<}\[)]?)$
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