Branch 的本质：指向 Commit 的可移动引用 | Git
本章覆盖：branch ref；branch tip；commit graph；lightweight pointer；create branch is cheap；branch does not copy project directory；current branch；HEAD；commit advances branch；branch naming。
本章知识点
- branch ref
- branch tip
- commit graph
- lightweight pointer
- create branch is cheap
- branch does not copy project directory
- current branch
- HEAD
- commit advances branch
- branch naming