This article from earlier this years makes sense of what going on at Mirriad it mentions all the tier1 clients with Magnite9 Nov 2023 16:50
Using Magnite’s proprietary LSA which IMO has "Mirriad inside" as Stephan mentioned RE the RNS the other day here's the AMC (which we know is the tier1 in the new agreement the other day) paragraph the article has testimony from other tier1's
Magnite is pleased to launch Magnite Streaming with the support of industry-leading clients:
“At AMC Networks, our rapid growth on ad-supported streaming platforms, with a programmatic first approach, requires modern ad tech infrastructure, built by those who understand the unique needs of media owners,” said Evan Adlman, Senior Vice President, Advanced Advertising and Digital Partnerships at AMC Networks. “We continue to be impressed by the Magnite team’s innovative solutions and outstanding client service and support. The launch of Magnite Streaming is an exciting development we hope opens more doors for publishers like ourselves.”
https://www.magnite.com/press/magnite-streaming/