When a List Item has a description, in addition to singular and plural labels, it's encoded in the profile as:*
<item idno="species_3927" enabled="0" default="0" type="concept">
<label locale="en_US" preferred="1">
<description>Type Species: Cercocebus fuliginosus É. Geoffroy, 1812.</description>
(*This is based on running "export configuration".)
However, this markup is throwing the validation error:
"Invalid content was found starting with element 'description'. No child element is expected at this point."