WARNING: THIS WILL CONTAIN SPOILERS. You should have played thru the ENTIRE quest missions of this season before proceeding.
It is also highly recommended you play thru the singleplayer campaign of Titanfall 2, as you will know who Ash is.
Alright with that said, I'm going to assume you're fine with reading anything below this.
Before activating Ash. the broken robot says a number of things. These might at first just sound like the remains of a robot from the Titan Wars, but if you keep listening (don't put the head on yet), it will reveal more dialog, including creepy phrases and some numbers.
Well, I took note of everything it says, including what happens when you put the head back onto the robot
I believe that there is some hidden message or secret with these, that likely would go beyond season 5/6, or even Apex Legends itself (yes, it might be related to Titanfall). For now, though, all there is is the dialog from the epilogue.
So, I want to make this a community effort to decode the code. Take a look at it, take a look at King's Canyon and maybe even World's Edge. Take a look at Titanfall while you're at it, idk. If you have any possible leads, or have anything to discuss, feel free to leave a comment on the doc or on this post (don't abuse the doc please or I'll close comments to the subreddit only).
Anything that might seem like a good lead I'll note down on the linked document. Hopefully, we can get somewhere on this, and it won't be a dead end, like the barcode banner on this subreddit 1 or 2 seasons ago. Good luck and thanks!
Source: https://www.reddit.com/r/apexlegends/comments/hreq9f/ashes_to_ashes_mystery/