Prior to 3.1.x the dat subdirectory didn't exist yet but data.base was present somewhere, possibly in the src subdirectory instead. I don't know whether it goes as far back as hack 1.x or even nethack 2.x. The source code for a bunch of old versions is present at https://nethackwiki.com/ but I'm not sure whether the data files are all there too. The source code for the most recent released version (3.6.7) is... Source: about 1 year ago

I am not sure what extra benefits the Steam version has, but the game is available for free either as download on nethack.org, or to play online at something like alt.org/nethack or hardfought.org. Source: about 1 year ago

You don't even need two people to play D&D, Nethack is great! Source: about 1 year ago

I've always been fond of the last quote on nethack.org. Source: about 1 year ago

It was discussed here last fall, when the home page for nethack.org was updated to mention it. The blurb includes a few other tiny screen shots and says the exhibit is scheduled to be open until mid-July. Source: over 1 year ago

Cinders || Trailer || DEKU - This dark fairytale follows the story of Cinderella, with a mature take on the tale. The story heavily emphasizes on the four women, the choices they had made and why they became what they are as you make various decisions throughout the story. Source: over 2 years ago

Cinders and Avian Attorney are good examples of what I am talking about. Source: over 2 years ago