It means that the Pope thinks the matter is unsettled. You don't. He does. So do I.
You chose to initiate a discussion with me about the apostle James in Gal. 1:19, and said that Paul didn't indicate that he's one of the Twelve. In post #4, I gave my argument for why he did, supported by the scriptural verses and crossover agreement between all my sources (early Christian Church Fathers), even if not every surname is listed by each individual source, which collectively prove that James in Gal. 1:19 was the apostle James of Alphaeus of the Twelve.
And, not only that. The following is all that they collectively prove:
(I) Jesus's brothers (kinsmen/relatives) Joseph, Simon, James, and Judas (Jude/Thaddeus) (Matt. 13:55, Mk.6:3) were the sons of His Mother's Spouse's brother, Alphaeus (Clopas/Cleophas), and his wife Mary of Clopas (Cleophas/Alphaeus), the sister in-law of Mary of Joseph (Jn. 19:25), and thus His cousins
(II) Jesus's cousins James and Judas (Jude/Thaddeus) (Matt. 13:55, Mk.6:3) also were the apostles James and Judas (Jude/Thaddeus) of Alphaeus (Clopas/Cleophas) of the Twelve
(III) Jesus's cousin James (Matt. 13:55, Mk.6:3) was not only the apostle James of Alphaeus of the Twelve, but also "James the Less" (Mk. 15:40), "James the brother of the Lord" (Gal. 1:19), "James the Just", "James the bishop of Jerusalem" (Ac. 15:13-21), and "James the author of the Epistle of James" (Jas. 1:1)
Therefore, no, it's not "James in Gal. 1:19 may well have been one of the Twelve", but rather he was one of the Twelve.
In Benedict's letter, it only says that there's some who dispute over the indenties of James of Alphaeus and James in Gal. 1:19. What has ever been proven that still isn't disputed by some? It's been proven, and repeatedly proven, for example, that the Earth is round, yet there are people who still dispute it, and/or claim to have proven it's flat. Therefore, this argument of "It's still disputed!" that you're putting up against post #4 is weak.
If you had something that actually disputes post #4, you would've presented it by now. So, this looks to be a case where despite being shown proof, what you'd would rather believe is stronger.