Supposedly it is, but I have not managed to get it to work.
I have followed instructions via:
man synthetic.conf
added the following to /etc/synthetic.conf (permissions: 644)
XYZ /Applications/MAMP/htdocs/system
XYZ2 /System/Volumes/Data/home
XYZ3 System/Volumes/Data/home
...trying different syntax and paths:
EXAMPLES
# create an empty directory named "foo" at / which may be mounted over
foo
# create a symbolic link named "bar" at / which points to
# "System/Volumes/Data/bar", a writeable location at the root of the data volume
bar System/Volumes/Data/bar
# create a symbolic link named "baz" at / which points to "Users/me/baz"
baz Users/me/baz
but after reboot I see no reference to these symbolic links:
ls -l
ps. confirming permisions:
root: read, write
wheel: read
everyone: read
I really need this to work. Any have any thoughts?