> libx11-dev is not installed by > default. As far as I'm concerned this is a non-bug.
Policy says: `Recommends' This declares a strong, but not absolute, dependency. The `Recommends' field should list packages that would be found together with this one in all but unusual installations. Today it is quite common (and I would argue that it is the most common case) to install -dev packages just to be able to compile some software. Thus it is not unusual at all not to need -doc packages. And in fact the vast majority of Debian packages only has a Suggests: relationship between -dev and -doc packages, including several xorg packages (xcb, xaw...) In the context where Debian gets installed more and more on space-constrained/ embedded platforms, installing it by default is even less relevant.