  EFTCAMB/EFTCosmoMC are publicly available patches to the CAMB/CosmoMC codes
implementing the effective field theory approach to single scalar field dark
energy and modified gravity models. With the present numerical notes we provide
a guide to the technical details of the code. Moreover we reproduce, as they
appear in the code, the complete set of the modified equations and the
expressions for all the other relevant quantities used to construct these
patches. We submit these notes to the arXiv to grant full and permanent access
to this material which provides very useful guidance to the numerical
implementation of the EFT framework. We will update this set of notes when
relevant modifications to the EFTCAMB/EFTCosmoMC codes will be released. The
present version is based on the version of EFTCAMB/EFTCosmoMC Sep17.
