How does a user that changes his own account password affect his login keychain?

When a user changes his own account password, the system will keep his login keychain password in sync.

The Archive option in the Finder creates compressed zip archive files.

The master password is used to reset local account passwords.

Time Machine starts with a full copy of the file system to the backup disk. Then it maintains a list of changes to the file system, and every hour copies only the changes to the backup disk. In the backup, it creates a simulation of the full file system using hard links for files that haven't changed.