According both to this page and to the Epic Games Store DRM page, the EGS version of This War of Mine is supposed to be DRM-free. However, this afternoon, I found evidence to the contrary. After installing it, I exited the Epic launcher program and tried to run the executable; nothing happened. (When I tried it on command line, it reported a segmentation fault.) Same thing happened when I tried to run it with the -EpicPortal parameter set. So then I tried running it via the Epic launcher, in case it was a "seemingly DRM-free but with hidden first-time setup through the launcher" scenario; but, while it ran fine, launching directly via the executable afterwards failed in exactly the same way as it did before. So, in short, launching via the executable doesn't seem to do anything, and I'm as such pretty sure the claim that the game is DRM-free is wrong.
(Maybe it was DRM-free at the time when that was written, and has subsequently been updated to have extra DRM? Since the claim is very specifically about running it via executable, which is the same thing which failed for me.)