The stakeholders are invented to designate different ‘actors’ who have an interest in the project. Even if such actors are not actively participated in project ‘life-cycle’ under some circumstances (state regulation authority, competitors, hackers for example).
According to ESSENCE (Kernel and Language for Software Engineering Methods), Stakeholders alpha belongs to the Using System and provide the Opportunity for the Solution in the System of Interest which they will use/consume. Stakeholders also support the Team in the Enabling System.
For the UX design projects, usual stakeholders are different types of business owners (operation managements, sales/marketing, legal), and different types of users, but also can include other actors.
Though Designers and Developers belong to the same Team in the Enabling System, Developers are often should be considered as stakeholders in UX as well. If we consider UX Design as an intermediary product inside Endeavor, the product produced by UX designers is not equal to the final Solution. UX design deliverables are the product by itself and are used by developers to produce the final solution.