tickMsg is used to signal a tick for updating progress

AliasManager manages primary names and their aliases

AppManager is an interface for managing registries. This interface defines methods to get the current registry URL and set the registry URL based on a

HomebrewRegistryManager manages the Homebrew registry

RegistryRegionSources is a map of package managers to urls

RegistrySources is a map of regions to registry regions

ShellFactory is a function type that returns a new ShellManager.

ShellManager is an interface for setting and getting environment variables in shell configuration files.

Zsh represents the zsh shell.

updateCompleteMsg is used to signal that the update is complete

updateMessageMsg is used to send update messages

updateModel defines the structure for the update model

updateResultMsg is used to signal the result of the update