User blog comment:Sarah Manley/Templates webinar followup/@comment-1613840-20130426185038/@comment-126761-20130429190312

Unfortunately, this was a question we didn't get a chance to clarify in the QA session.

Two potential things this may refer to are:

Some templates simple won't show up on a template page because of their nature. For example, they might be a bit of layout code that only has an obvious effect when used on an article.

Other might not show up because the template has been wrapped in tags. The code within one of these tags will only be used when put on an article page - it'll be blank on a template page. You can read more about the noinclude, includeonly and onlyinclude tags on Wikipedia's templates help page here.