Refusing to talk about Fallout 4 or Elder Scrolls is one thing, but refusing to discuss what would already be a secret codename for a project is just dumb. A simple internet search would show that the terminology isnt out there, so how would any member of the public know to even ask the appropriate question? The same goes for Project Greenheart. A quick Googling reveals that the only mention of something similar is for the Greenheart Project which seems to either be a bunch of solar-powered cargo ships, a volunteer program for teaching children about nutrition or an Indiegogo project. There is not a single mention of Bethesda or even computer games in general. Anyone working on Fallout/Elder Scrolls would know the project titles and could easily link the two together, so there would be no need to mention them alongside in a memo. Its not like anyone working on Van Buren didnt know they were working on Fallout 3 (not the Fallout 3 that was eventually released though).
