Where are attributes documented?
Where are attributes documented? Why does my attribute not seem to make a difference?
In general, attributes are documented in a chapter of the reference manual; some are also documented in the sections in which the language feature for which they are relevant is described. However, at present not all of them are documented.
Some projects with forks of Dafny may introduce attributes of their own. Keep in mind, that any attributes not recognized by Dafny are silently ignored, to allow for such extension.