diff --git a/src/display.cpp b/src/display.cpp
index fae4dc9..09aa812 100644
--- a/src/display.cpp
+++ b/src/display.cpp
@@ -1,3 +1,4 @@
+// library to be used by "keyboard_cmd.cpp"
 #include <ncurses.h>
 #include <string>
 #include <geometry_msgs/Twist.h>
diff --git a/src/display.h b/src/display.h
index 2c88eda..7741659 100644
--- a/src/display.h
+++ b/src/display.h
@@ -1,3 +1,4 @@
+// library to be used by "keyboard_cmd.cpp"
 #ifndef CURSES_DISPLAY
 #define CURSES_DISPLAY