It is used to build and maintain a list or lists of pages—primarily for the sake of the lists themselves and their use in article and category maintenance. It is not part of the encyclopedia's categorization scheme.
These categories are used to track, build and organize lists of pages needing "attention en masse" (for example, pages using deprecated syntax), or that may need to be edited at someone's earliest convenience.
These categories also serve to aggregate members of several lists or subcategories into a larger, more efficient list (discriminated by classifications).
Typically, tracking categories are automatically populated by templates invoked in pages or by the MediaWiki software (see Special:TrackingCategories for an overview of the latter).
Administrators: Please do not delete this category as empty! This category may be empty occasionally or even most of the time.
This is an error tracking category for {{Taxonbar}} templates which do not have a |from#= parameter corresponding to the Wikidata item (also referred to as 'entity' or 'QID') which points to the Wikipedia article.
Possible reasons for this include:
it is most likely that the Wikidata item that once pointed to the categorized page has changed, or
the page was copied as a template and the creator forgot to update the |from= parameter, or
Wikidata has separate items for a taxon and a topic associated with the taxon (e.g., a disease and its causal agent, or a vegetable and the plant species that produces it), and the Wikipedia article is linked to the associated concept at Wikidata.