A new video has been uploaded:
This one shows the Orbiter side of things, and the relevant code in the Weather Plugin that intercepts events. The only part I didn't show (I forgot to put it in there) was the code for Get_Weather_Data...nothing special there, you can see it in src/Weather_Plugin, it just gets the data out of the weather data map, and returns it, in addition to calling CMD_Set_Variable() to set the Orbiter variables. It knows where to send the message, because the Orbiter is sending the Get Weather Data Message, (the Orbiter Device ID becomes the From device).
Variable substitution is shown, as is an explanation of Alternate Graphic files, and how they are used with Set Graphic Image, to provide the iconic display.
Let me know if you have any questions,