The Future Perfect Continuous Tense, also known as the Future Perfect Progressive Tense, is used to describe an ongoing action that will continue until a specified time in the future and will be completed at that time. It emphasizes the duration of an action that starts in the present or past and will continue up until a certain point in the future.
The Future Perfect Continuous Tense is formed by using the auxiliary verb "will" or "shall" (in the first person singular and plural), followed by "have been," and the present participle form of the main verb (-ing form).