As long as library authors follow the normal Boost guidelines for placing the necessary files for using, building ( for non-header only libraries ), testing, and documenting their library I really don't see why an author cannot add to their library whatever other files they want in whatever place in their library structure they want to put it. Can it really be such a big issue that this should not be allowed ? And, if so, why ? If the real issue being objected to is that the placement of additional files gives the end-user an impression that Boost libraries generally support additional things which an individual library supports with the additional files, wouldn't it just be better to encourage and/or require that an individual library developer document the additional files as personal extensions to what Boost requires.