Look at the console.
This could be a breakthrough.
The 5 symbols may mean something, quick someone type this on Halo Waypoint’s console!
Another Halo Wars cutscene.
We’ve known for a long time my fellow reclaimer.
I see this is your first post. And I know the “Secret Terminals Mega-Thread” isn’t on the front CEA page anymore. But your a little late. There was a huge hunt where some of the best of the Halo Community deciphered the Forerunner symbols from the Secret Terminal Input Device on Waypoint. They even found a secret “12th” terminal that was shortly locked by 343i after they accessed it. They made a complete translation of the symbols, translated the codes into 5 letter Halo words, and now know the Forerunner Alphabet… or as it is translated into Human language.
What happens when the code entered from the first cutscene “Judgement Day” is entered?
I tried the codes from the Halo Wars cutscenes a while back. Nothing happens when you enter them.
If any other terminals are found they are frozen/ taken down by 343i. We can’t blame stosh so blame the coffee drinking pro Frank O’C. 
So found this thread interesting. I didn’t know this info