Some question regarded to new Terminal App / Virtualization

1.) Is the debian image, which needs to be downloaded beforehand using the terminal, provided by Google?
If yes: Any concern regarding tracking and invasion of privacy ?
If no: Was the image degoogled?
2.) Where can I find more, what can be done with/in this Linux environment in the moment?
3.) When starting the app, 'droid' is the default user. What is the passwd for this UID?
4.) What should I prevent to do in this early stage to no to trash the system (beside obvious things, which
now one should do to a running UNIX/Linux system...)
5.) How can I make USB devices accessible in this Linux environment?
6.) What keyboard app is especially suitable for being used in the Linux environment? Any recommandations?
Cheers!