MS Android Patents Revealed
As I mentioned earlier in this discussion, Barnes & Noble did hold off Microsoft's Android patent demands in 2011, and formed a joint venture with them as part of the ongoing efforts by MS to keep the patents secret. But then the venture was dissolved, and they parted ways about a year later, and, it seems, the patents remained secret then:
https://www.businessinsider.com/barnes-and-noble-pays-62-million-to-get-out-of-microsoft-deal-2014-12
However, the patents were revealed by Chinese government regulators per this 2014 ZDnet article ( https://www.zdnet.com/article/310-microsoft-patents-used-in-android-licensing-agreements-revealed-by-chinese-gov/ ). The linked ArsTechnica article spells out many of the patents' disclosed, and that many were acquired from Nortel's portfolio via the MS participation in the Rockstar consortium that acquired a huge cache of patents with Nortel's bankruptcy liquidation:
"The company has never revealed the patents and fees centered within licensing deals, unless required to do so in the courtroom. However, documents posted on the Chinese Ministry of Commerce (MOFCOM)’s website detail the full range of patents included within licensing agreements. As reported by Ars Technica, the patent lists were submitted as part of the Chinese government's review of the purchase of Nokia's handset division by Microsoft for $7.2 billion.
Chinese regulators approved the deal in April after examining whether Microsoft's licensing agreements could be used in an anti-competitive fashion, and whether Nokia might be tempted to ramp up the costs of licensing.
The patents, which are found on the Chinese language version of the website, include 73 standard-essential patents generally used in mobile technology, as well as 127 Android-implemented patents -- both developed by Microsoft and acquired by participating in the Rockstar Consortium. In addition, a number of non standard-essential patents were examined by Chinese regulators, including 68 patent applications and 42 issued patents."