What is perfect in present perfect continous tense? [duplicate]

First of all, (though not for the first time),

• "Present Perfect" is not a tense,
• "Perfect" is not a tense,
• "Present Continuous" is not a tense, and
• "Present Perfect Continuous" is not a tense.

Present is a tense, and Past is a tense. Those are the only tenses in English. Tenses change the verb itself, instead of adding yet more auxiliary verbs.

Everything else is a Construction.

• the Perfect Construction uses a form of have plus the Perfect Participle of the next verb.

  • I have eaten.

• the Continuous (or Progressive) Construction uses a form of be plus the Present Participle of the next verb.

  • I am eating.

• These can be put together, if done in the proper order (Perfect before Progressive)

  • I have been eating.

In Portuguese, past continuous and past simple are called respectively "past imperfect" and "past perfect".

I ate. (nothing stopped me before I finished)

I was eating. (when something happened and made me stop)

"I have eaten" sounds like "I ate", but the focus in on the moment (consequence of eating), not in the past.

Present perfect is used to describe what's finished at the time of speaking. Perfectly finished.