The result is a List with currently three items:

1. The first item in the list is 0 if the character at the position {lnum} and {col} is not part of a concealable region, 1 if it is. {lnum} is used like with getline().
2. The second item in the list is a string. If the first item is 1, the second item contains the text which will be displayed in place of the concealed text, depending on the current setting of 'conceallevel' and 'listchars'.
3. The third and final item in the list is a number representing the specific syntax region matched in the line. When the character is not concealed the value is zero. This allows detection of the beginning of a new concealable region if there are two consecutive regions with the same replacement character. For an example, if the text is "123456" and both "23" and "45" are concealed and replaced by the character "X", then: call returns synconcealed(lnum, 1) [0, '', 0] synconcealed(lnum, 2) [1, 'X', 1] synconcealed(lnum, 3) [1, 'X', 1] synconcealed(lnum, 4) [1, 'X', 2] synconcealed(lnum, 5) [1, 'X', 2] synconcealed(lnum, 6) [0, '', 0]