The addition of an opacity mask feature in Spine has been a popular request among users, as it would allow for more flexible and visually appealing effects by cropping layers based on transparency. However, implementing such a feature across all runtimes is complex and has not been prioritized in the short term due to the significant workload involved. While some users have managed to create custom solutions by modifying Spine's runtime library, these solutions do not integrate seamlessly with the Spine editor, limiting their usability. The Spine team is aware of the demand for this feature, but it remains outside of their immediate plans as they focus on other priorities.