Here's how to look at branches: every commit is like a branch, and a branch is just a pointer to a specific commit (so a branch is basically a commit with a pointer to a commit)
main --- c --- c1
reed creates a commit with a pointer to c1
, so we add a 'branch' which is just a commit (c2)
c1 <- c2 <--> r1 -- r2 --r3 --> reed makes a pull request