in fact if ESPAlexa v2.7.0 is installed under arduino and if Espalexa.h, EspalexaDevice.cpp, EspalexaDevice.h are removed in B4R directory rEspalexa, compilation is OK with B4R
i will make a new delivery of rEspalexa v2.7.0 in this way, but i don't understand why compilation is NOK when ESPAlexa library is in rESPAlexa directory.