CZ:Article-specific subpages
Article-specific subpages are tab-navigable subpages (i.e. they show up in the standard subpages navigation bar at the top of each page in a cluster) which are not in the system-wide list of standard optional subpages (see Template:Subpage list); they therefore have to be specially configured in each article which uses them.
Up to three different additional article-specific subpages per article may be defined.
Mechanics
There is a system-wide list of available article-specific subpage name/types below. Pick a suitable one, or if no suitable one exists, add a new one, using the instructions there.
To add the article-specific subpage to the article, edit the Metadata page for that article; edit the fields "tab1 = " and "tab1url = " (or tab2, or tab3, as the case may be) to contain that name. (Up to three different article-specific subpages can be designated at the moment.) Save the Metadata, and go back to the article page.
Note that these subpages, like any other subpage which is part of a cluster, must have a {{subpages}} header in the first line for the subpage navigation bar to appear.
List
For technical reasons, we need to have a system-wide list of defined article-specific subpages. That list is currently here.
Before defining a new subpage type, it's probably worth dropping a line to the Forums to see what people think. Also, if you think this is a subpage type that might be reasonably widely used (on, say, 1% of all pages), it probably ought to be made a system-wide optional page; follow the directions at CZ:How to add a new subpage type.
Currently defined
Defining a new article-specific subpage
First, pick a one-word name for the new subpage type. Add it to the list above (in alphabetic order, please), with a brief description of what it is for. (A full page describing it, linked to from the list, is nice, but not necessary.)
Next, each new article-specific subpage type must have the correct associated header and footer templates for it to functional correctly. They have names of the form {{Isotopes header}} and {{Isotopes footer}} (this example is for the article-specific Isotopes subpage). To do this, use the following links:
Click on the links (in a new window, so you can continue to read the instructions here), edit the URL in the URL bar of your browser to replace the "NEWNAME" with your new article-specific subpage name, open that "edit" page, set up your new subpage's header and footer (they may be blank) and save them.