However, since I was the Project Lead for the Spyglass browser team, there is one correction I can offer: We licensed the Mosaic code, but we never used any of it. Spyglass Mosaic was written from scratch.
In big picture terms, Marc's recollections look essentially correct, and he even shared a couple of credible-looking tidbits that I didn't know.
It was a crazy time. Netscape beat us, but I remember my boss observing that we beat everyone who didn't outspend us by a favor of five. I didn't get mega-rich or mega-famous like Marc (deservedly) did, but I learned a lot, and I remain thankful to have been involved in the story.
While Marc recounts that Microsoft offered for Spyglass to sell "Microsoft Mosaic" as an add-on while still offering your own independent version - despite MSFT eventually making its own browser free anyway - is there anything within that part of the larger story that you would elucidate to tell differently, or clarify deeper into its weeds? It was always one of the parts of the story that was more glossed over.