The git repository contains a z80 assembly branch instead of the newer, more complete Forth codebase.

In the directory extracted from the .tar.gz...

See the current branch
$ git branch
         MCMP
         anonword
         doloop
       * master
         sdc
         wip
         z80asm

Checkout the 'z80asm' branch using:
$ git checkout z80asm
       Switched to branch 'z80asm'

Now, have another look at the current branch using:
$ git branch
         MCMP
         anonword
         doloop
         master
         sdc
         wip
       * z80asm

Now the files in your git repository are updated (in this case back-dated) to
the z80asm branch.