Starmer & Co have always been soft on trying to push media regulation, unlike Corbyn's admin and a number of the other smaller parties, but for quite some time they were still supporting a sort of soft opt-in approach: Example from Feb of this year

Then, when the election date was announced, suddenly all the media regulation policy proposals were absent from party materials and ministers wouldn't even answer questions on it: June exmaple

During the election campaign the Murdoch empire and others in the right wing press swang fully behind Labour for the first time since Blair. Everyone in media and politics circles were saying a deal was done to oppose any media regulation in exchange for their support.

Then in late July the iNewspaper (formerly Independent) officially ran the story that a deal had been agreed between senior Labour Party officials and at least Murdoch. That story is paywalled, but here's some more stories and analysis from the next day when the press started asking Labour if this was true and they repeatedly dodged the question and refused to deny it: 23rd July