Remarkable

Be careful with this, the file contains settings other than the sync account.

In particular, it contains the SSH password shown in the settings screen, which is supposed to be the same as the actual SSH password, but may not be. Whenever the OS is upgraded, the "new" OS will generate a new random password, set that password for the root user, and update the xochitl.conf file with that new password.

As an example, let's say that ...

• Tablet A's password is aaaaa, and its xochitl.conf file contains DeveloperPassword=aaaaa.
• Tablet B's password is bbbbb, and its xochitl.conf file contains DeveloperPassword=bbbbb.

If you copy xochitl.conf from tablet A to tablet B ...

• Tablet B's password will still be bbbbb, but its xochitl.conf file will now say DeveloperPassword=aaaaa.
• This means that the settings screen will tell you that the password is aaaaa.
• If you are relying on the settings screen to remember the password, you won't be able to SSH into tablet B anymore (at least until the next time its OS is upgraded, and a new random password is installed).

Ways around this:

• After copying xochitl.conf from tablet A to tablet B, edit the xochitl.conf file and put the correct password back on the DeveloperPassword= line. This will make the settings screen show the correct password. (You may need to restart xochitl in order for it to start showing the updated password in the settings screen.)
• Manually reset the tablet's password to aaaaa, so that the settings screen is accurate.
• Set up SSH keys on both tablets, and never need to worry about the password again, even after OS upgrades.

FWIW on my own tablets, after each OS upgrade I manually change the root user's password to something which (1) does not match the settings screen, and (2) is recorded in 1Password in case I ever need it. I also have an SSH key that I use on all of my personal systems, and have installed the same authorized_keys file on both tablets.