Detected a unquoted template variable as an attribute. If unquoted, a malicious actor could inject custom JavaScript handlers. To fix this, add quotes around the template expression, like this: "{{ expr }}".
<div id="posts-list-{{ .category.name | urlize }}" class="archive" data-category="{{ .category.name }}" data-parent-categories="{{ delimit $ancestors "," }}" style="display: block;">