Welcome to the ZDoom Forums!

I deleted 3 more files:

Readme.Carmack because it's identical to readme.asm
colors.txt because it's a copy of the color definition lump in the WADSRC directory.
classes.txt because it was hopelessly outdated.

But that's all that I feel comfortable to remove.
I don't believe that history.txt and zdoom.txt still have some use but they are of some historic value, if anything.

These files aren't even distributed with the binaries. They are only in the SVN and source distribution (and to be honest, I doubt anyone really cares about them.)

Hmmm, maybe the files should be replaced with either a few select wiki articles (pulled each time an SVN package is compiled) or simply brief installation instructions following by a link to the wiki.

No, Nightmare. These files are actually part of the current SVN! Yes, they haven't been updated in 9 years but they are still there from the good old v1.22 times. (And yes, the files he mentioned could indeed well be deleted.)

Maybe you should modify the docs and "modernize" them, see if Randy will distribute them in his newer builds. I bet you he would.

The reason why those files are outdated is -- surprise! --- because they're from an old version of ZDoom. By that, I don't mean the recent versions of ZDoom are including docs from an older version, I mean those files are from an old version of ZDoom that you installed, and are still there because more recent versions of ZDoom don't include a docs /directory at all (the only text files included in the .zip are buildlic.txt and doomlic.txt) and hence they haven't been overwritten.

This may sound stupid but today I accidentally opened zdoom.txt and had some good laughs while reading this outdated 9 year old information.

I think some of the things in there should better be deleted, particularly zdoom.txt, notes.txt, history.txt, foo.txt. But even most of the other files in there are hopelessly outdated and no longer really relevant.