Template:Notice

Notice

Use {{notice|type=|subject=|comment=}}

type (required), currently supported: historical, under-construction, outdated, user-blocked, archive, nominated-for-deletion
subject (optional), defaults to page, can also be section, ... (for nominated-for-deletion, defaults to "test project")
comment (optional), any extra text after the default notice text
expiry (optional), only for type=user-blocked
archivelink (optional), only for type=archive, link destination of current discussion page

For a custom notice, add text as a first paramter: {{Notice|42 is the answer.}}