[xcart-dev]

It was indeed include.search.php.

For anyone who stumbles on this thread I wanted to have whole word matches but only in the extra fields. So I changed:

foreach ($data['extra_fields'] as $k => $v) { 
$condition[] = '(' . $sql_tbl['extra_field_values'] . '.value LIKE \'%' . $data['substring'] . '%\' AND ' . $sql_tbl['extra_fields'] . '.fieldid = \'' . $k . '\')';
            }

To:

foreach ($data['extra_fields'] as $k => $v) { 
$condition[] = '(' . $sql_tbl['extra_field_values'] . '.value REGEXP \'[[:<:]]' . $data['substring'] . '[[:>:]]\' AND ' . $sql_tbl['extra_fields'] . '.fieldid = \'' . $k . '\')';
            }

The Regexp now demands that only whole words are found rather than words 'like'