Stubs are articles that exist but are too incomplete to fully answer their title's question. This is a maintenance category: it collects pages flagged as stubs so editors can find and expand them.
How a page joins this category
Pages are added automatically, not by hand. Every entity infobox accepts a stub parameter; setting stub=yes (any non-empty value works) adds the page here. Do not add [[Category:Stubs]] to a page directly.
Clearing a stub
Fill in the missing data and prose until the page answers its title's question above the fold, then remove the stub parameter from the infobox. The page leaves this category on its next save.