When configuring automation rules, it's possible to create a separate section of the rule and perform actions on related issues - this is referred to as branching. This is in reference to the rule no longer executing in a linear fashion, but instead expanding out to multiple paths.
For example, a rule that’s triggered when an issue transitions to Done could also have a branch that performs separate actions on that issue’s subtasks.
In the screenshot above, we have an automation rule consisting of a trigger, an action, and a branch.
The Scheduled trigger and Create a new task action are the main line of the rule.
The For all created issues branch allows the rule to add a comment on the task that was just created. Without this branch, we wouldn’t be able to add a comment on the new task.
Nesting: Branches can’t be nested in one another, which means you can’t have a branch inside another branch.
If/else condition: and don’t support the use of the If/else block condition.
Isolation: Branches are isolated. Any changes that occur in a branch won’t be visible to the main rule, or any other branch. For example, if a branch has a Create variable action, the created smart value can be used in that same branch, but can't be used in the main rule, nor in other branches.