The `av` CLI tool manages stacked Git branches and their associated GitHub pull requests in an automated workflow. It allows developers to create dependent branches, automatically rebase child branches when parents change, synchronize local state with GitHub (fetches, pushes, prunes merged branches), and interactively reorder or squash commits across a stack. The system uses a local JSON file database (`av.db`) to persist branch metadata and PR associations, a GraphQL client to communicate with GitHub, and a Bubbletea-based terminal UI for interactive prompts and progress spinners. It consists of Cobra command definitions, a git operations wrapper (mix of `go-git` and direct exec), and a state-machine sequencer for multi-step rebase operations with conflict handling. The architecture is modular with clear separation between git operations, GitHub API, state management, and user interface, making it a solid example of a domain-specific developer tool.