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.