If it comes from a project management tool such as Jira or Clubhouse, I normally start the name of the branch with the ID of the card in the tool:
LPF-129-save-draft-of-formBut if there's no ID to relate, I just use the feature or the thing to do in the name:
save-draft-of-formBTW, starting a branch name with b/ is quite weird because you know it's a branch from the get-go.