For what are presumably legal reasons, all the more obscure to me for that, the document itself has only been published in Origins, "the documentary service of Catholic News Service." It is available online only to subscribers. When I last worked for the Church I had a hard-copy subscription as a perk, but these days that's a luxury I cannot afford. As soon as it's available, I shall read the whole report at the Belmont Abbey library and comment again. In the meantime, the CNS story I've linked above contains numerous quotes you can read for yourself, and says enough to highlight the principal theological points.
Essentially, the report gives reasons explaining CCC §1261:
As regards children who have died without Baptism, the Church can only entrust them to the mercy of God, as she does in her funeral rites for them. Indeed, the great mercy of God who desires that all men should be saved, and Jesus' tenderness toward children which caused him to say: "Let the children come to me, do not hinder them," allow us to hope that there is a way of salvation for children who have died without Baptism. All the more urgent is the Church's call not to prevent little children coming to Christ through the gift of holy Baptism.
Two fundamental points must be stressed. First, we are "allowed to hope" that infants (and any others incapable of exercising moral responsibility) who die unbaptized will be saved; second, if there is a way of salvation for such persons, we do not know what it is. The latter is obvious; the former entails theological developments of a kind that generates controversy.
Specifically, the document says, the dogmas of the necessity of baptism and extra ecclesiam nulla salus need to be "nuanced." The two are closely interrelated inasmuch as sacramental baptism is understood by Tradition as the ordinary means of incorporation into the Church. Now the necessity of formal, sacramental baptism has always been relativized, at least implicitly, by the Church's recognition of baptism by blood and explicit desire; the question is whether it can or ought to be relativized further. The key development in such relativization has been the insistence by the Church, over the last couple of centuries, that God does not condemn anybody who dies without having seriously sinned. Those who thus die, but also without baptism, must therefore avoid damnation in some way other than by formal, sacramental baptism.
Limbo was a medieval theory developed to explain how such people, mostly infants, could avoid the suffering of hell without being incorporated into the Church by formal, sacramental baptism. What the new ITC report does is allow that such people might be incorporated into the Church by means other than formal, sacramental baptism. Such an allowance obviates the need to posit a permanent limbo for such people. It is a development, one that does not negate previously defined doctrines but continues the process of refining their scope. In defense of the Church, I have written about that process before.
Knowing the world of Internet theological controversy as I do, I'll probably have to do it again about original sin as inherited "guilt."