I may be missing something obvious and also I haven't studied the case into details. But on your github repository I can see the rubric.mustache that correctly wraps the list items. However, in the snapshots repository which is what the code precheck uses, such a wrapper is not present. Could that be related?
General developer forum
Mustache template for list item causes a mustache_lint warning
Hi David, there are two complications to what you're noticing. The first thing is that I have pushed new code since posing the question, and the second thing is that the rubric.mustache includes a list_item.mustache that still causes a warning in the precheck. The new snapshot is at https://git.in.moodle.com/pluginsbot/moodle-plugins-snapshots/blob/007ad633ede708abd3cddd3f3575650078b4c1bb/blocks/filtered_course_list/templates/list_item.mustache#L1.
I am now also getting a second precheck warning, again because the precheck does not consider the context into which an element is included. The new message is:
An element with “role=tab” must be contained in, or owned by, an element with “role=tablist”.
Should I be handling something differently? Or is it just a limitation of the precheck?