This message is used as a category name for a tracking category where pages are placed automatically if the expanded size of the templates they contain exceeds the limit.
When templates are expanded, there is a size limit for the number of bytes yielded. Usually that occurs from excessively nested templates, recursive templates, or ones having x-zillion of #if #case or similar contructs in them. When the wikicode parser detects this, it outputs a red warning message to the page.
See also:
Några av mallarna kommer inte att inkluderas.")
Sidor som inkluderar för mycket mallkod