The collection topic filter defines where the filter widget will appear and which collections it applies to.
Encompass the collections that apply to the filter withing a style helper entitled ui-x-tag-filters.
{{#style "ui-x-tag-filters"}}
...
{{#style "whatsnew-collection-list"}}
add-filtering-tags-md,
add-filtering-to-a-collection-md,
add-filtering-md,
add-filtering-group-md
{{/style}}
...
{{/style}}
This filter section can appear anywhere in a topic. The filter widget will appear at the beginning of that section.