Or it has been installed more recently than this documentation. In
this case, you need to configure and install again this
documentation.
To install hpp-gepetto-viewer, you need either
to get the source code through git: git clone git@github.com:humanoid-path-planner/hpp-gepetto-viewer, then configure, compile and install the package.
install it through robotpkg: cd robotpkg/graphics/hpp-gepetto-viewer; make update
Note that you will need to configure and install again this
documentation to activate the link to hpp-gepetto-viewer.