intvdocs
These documents were originally created on MS-DOS, using text and graphics characters. They have been converted from cp437 encoding to UTF-8 encoding, to be rendered properly on modern computers
This was accomplished with the help of this website:
http://codelobe.com/tools/cp437-converter
For best results, you can view them in a modern text editor like Visual Studio Code, or just view them in raw mode on github.