LOCAL_C_INCLUDES contains multiple header files directory What does this mean?

            
Reads as follows:
LOCAL_C_INCLUDES: = $ (LOCAL_PATH) / pjlib / include / $ (LOCAL_PATH) / pjlib-util / include / \
....$ (LOCAL_PATH) include / $ (LOCAL_PATH) .. / \
$ (LOCAL_PATH).. / Third_party / srtp / include $ (LOCAL_PATH).. / Third_party / srtp / include \
$ (LOCAL_PATH).. / Third_party / srtp / crypto / include $ (LOCAL_PATH).. / Third_party / build / srtp / \
$ (LOCAL_PATH).. / Third_party / build / speex / $ (LOCAL_PATH).. / Third_party / speex / include \
$ (LOCAL_PATH).. / Third_party /
I know that contains a header file, then LOCA_SRC_FILES inside the header file is in this header file directory to find the header files need to be included, then so many header files, then the corresponding header file directory how?