The SCons wiki has moved to https://github.com/SCons/scons/wiki/UpdateGuide
CAUTION: Only try this step if you have the toolchain for building the documentation. The packages needed are discussed in DeveloperGuide/Documentation. It's quite a list.
The following steps verify that the user guide sources (some of which are generated from other files) are up to date.
FIXME (This will probably be reworked to be part of the build step.)
$ python bin/scons-doc.py --diff $ python bin/scons-doc.py --update