This is atracking category.

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 theencyclopedia's categorization scheme.

More information:

• This category ishidden on itsmember pages—unless the correspondinguser preference (Appearance → Show hidden categories) is set.
• These categories are used to track, build and organize lists of pages needing "attentionen 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 (seeSpecial: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 a tracking category for{{cite journal}} templates and for{{citation}} templates that use the|journal=,|doi=, and|page(s)= parameters.Module:Citation/CS1 emits this category when the value assigned to|page= or|pages= appears to be an article number and not a page number.

Module:Citation/CS1 skips|page(s)= values that:

• are ranges separated by underscore, hyphen, emdash, endash, figure dash, or minus character
• are comma- or semicolon-separated lists of pages
• have external urls
• are digit-only values less than 10000

For those templates that are not skipped, the module compares the trailing (rightmost) characters of the|doi= value against the whole value of the|page(s)= value. There are a variety of tests:

• five or more digits –|page=100393 matches|doi=10.1016/j.gfs.2020.100393
• five or more characters –|page=CD004052 matches|doi=10.1002/14651858.CD004052
• five or more characters with e prefix (case insensitive) –|page=eadl0822 matches|doi=10.1126/sciadv.adl0822
• exactly eight digits; modified by the test to insert a dot between the 4th and 5th digits –|page=20170301 modified to2017.0301 matches|doi=10.1098/rsbl.2017.0301
• CD prefix (case insensitive) followed by (typically) six digits; modified by the test to append .pubn suffix wheren is a single digit –|page=CD005216 matches|doi=10.1002/14651858.CD005216.pub2

To fix cs1|2 templates that emit this maintenance message/category, ensure that the value assigned to|page= is an insource location page number. When the page number isnot a page number, change|page= to|article-number=.

Pages with this condition are automatically placed in Category:CS1 maint: article number as page number.^[a]

By default,Citation Style 1 andCitation Style 2error messages are visible to all readers andmaintenance messages are hidden from all readers.

To displaymaintenance messages in the rendered article, include the following text in your commonCSS page (common.css) or your specific skin's CSS page and (skin.css).

(Note to new editors: those CSS pages are specific to you, and control your view of pages, by adding to your user account'sCSS code. If you have not yet created such a page, then clicking one of the.css links above will yield a page that starts "Wikipedia does not have auser page with this exact name." Click the "Start the User:username/filename page" link, paste the text below, save the page, follow the instructions at the bottom of the new page on bypassing your browser's cache, and finally, in order to see the previously hidden maintenance messages, refresh the page you were editing earlier.)

:root.mw-parser-output.cs1-maint{display:inline;}/* display Citation Style 1 maintenance messages */

To display hidden-by-defaulterror messages:

:root.mw-parser-output.cs1-hidden-error{display:inline;}/* display hidden Citation Style 1 error messages */

Even with this CSS installed, older pages in Wikipedia's cache may not have been updated to show these error messages even though the page is listed in one of the tracking categories. Anull edit will resolve that issue.

After (error and/maintenance) messages are displayed, it might still not be easy to find them in a large article with a lot of citations. Messages can then be found by searching (with Ctrl-F) for "(help)" or "cs1".

To hide normally-displayederror messages:

:root.mw-parser-output.cs1-visible-error{display:none;}/* hide Citation Style 1 error messages */

You can personalize the display of these messages (such as changing the color), but you will need to ask someone who knows CSS or atthe technical village pump if you do not understand how.

Nota bene: these CSS rules are not obeyed byNavigation popups. They also do not hide script warning messages in the Preview box that begin with "This is only a preview; your changes have not yet been saved".

• CS1 maintenance

• Hidden categories
• Tracking categories
• Template Category TOC via Automatic category TOC on category with 901–1200 pages
• Automatic category TOC generates standard Category TOC