BookBarbarian
Expert Long Rester
He explicitlytold the player that the files were free game to reveal as his PC's personal knowledge. As a new player coming into an existing game they may have though it was things that already happened to get them up to speed, information the DM wanted to use the new PC to introduce, or some other reason why they are being sent this in-depth knowledge.
So, let's move past this antagonistic step 1 where the DM climbs down the new player's throat for following directions. Assuming that the answer is "I did what you told me to", what's step 2?
Yep. Sorry about that. I totally glossed over that part of the OP. /facepalm. I'll edit my post.
Ok... Step 2, but really Step 1 because my previous Step 1 was a bad idea. I would send the same info to everyone else in the group. Might as well let them all have the same info at this point. Next I would come up with a good reason why the Party could have found out this information. Perhaps they found a plan, uncoded it and now have this info,or maybe they interrogated somebody for it. Have fun with this part.
Then i would ask myself what would my BBEG do if he found out all his plans had been found out. Abandon them? Keep them but start implementing them faster to get the drop on the PCs? A little of both?
BBEGs are after all conniving types that are master manipulators and such. Decide how he would act to this happening.