[CMake] add_library ALIAS

I am trying to figure out exactly what this line is for in the cmake file of the github json project here -> https://github.com/nlohmann/json/blob/develop/CMakeLists.txt#L48 add_library(${PROJECT_NAME}::${NLOHMANN_JSON_TARGET_NAME} ALIAS ${NLOHMANN_JSON_TARGET_NAME}) Specifically with this

[CMake] Cmake Boost::boost target PRIVATE link, forcing dependency on client

I am having a problem with make 3.12 (windows) and cmake version 3.13.0-rc2 (linux). I am attempting to link boost headers privately to a static library, which is then linked by a client executable, that I do not want to depend on boost. According to the docs, the find_package(Boost) provides