You can find the 5-2 opinion in Wisconsin Voter Alliance v. Secord here. From the introduction to the majority opinion by Justice Protasiewicz:

The Wisconsin Voter Alliance seeks access to Notice of Voting Eligibility forms (“NVE forms”) under Wisconsin public records law. Courts use NVE forms to communicate to election officials or agencies that a person subject to guardianship proceedings has been found incompetent to vote. The Alliance filed a public records request with the Walworth County register in probate and brought this mandamus action seeking disclosure of completed NVE forms. The circuit court held that the forms should not be released, and the court of appeals, on remand from this court, affirmed.

Our decision today is rooted in the legislature’s choice to protect the privacy of individuals subject to guardianship proceedings. The legislature said, with limited exceptions, “court records pertinent to the finding of incompetency are closed.” WIS. STAT. § 54.75 (2021–22). We hold that the NVE forms at issue here are “closed” under that statute. Thus, the Alliance does not have a right to the forms under our public records law, and the Alliance is not entitled to a writ of mandamus.

UPI has this story on today’s decision, and the Milwaukee Journal Sentinel this one, which notes that the leader of the group seeking the records “was previously hired by former state Supreme Court Justice Michael Gableman as an investigator in a fruitless, taxpayer-funded review of the 2020 election.”