At 11:44 a.m., the account labeled “Pete Hegseth” posted in Signal a “TEAM UPDATE.” I will not quote from this update, or from certain other subsequent texts. The information contained in them, if they had been read by an adversary of the United States, could conceivably have been used to harm American military and intelligence personnel, particularly in the broader Middle East, Central Command’s area of responsibility. What I will say, in order to illustrate the shocking recklessness of this Signal conversation, is that the Hegseth post contained operational details of forthcoming strikes on Yemen, including information about targets, weapons the U.S. would be deploying, and attack sequencing.
From TFA.
The discussion itself wasn't transacting classified documents as such. But as Goldberg makes clear, information of both general sensitivity and immediate tactical significance was disclosed.
It was confirmed (under oath) that there was no classified information shared, however, the contents of the messages could not be shared with the Senate Select Committee on Intelligence as it is classified information.