Is there a canonical definition of what makes a game fringe for this forum's purposes
My main focus has generally been digging into the stories around games that are outside the normal scope of a "games industry" history. Freeware, homebrew, and fangame stuff most obviously, but with enough vague wiggle room to dig into basically anything that doesn't get written about enough. (For example, I have a strong desire to really dig into the guts of how the shareware industry actually worked, despite, you know, Doom being among the most well-documented games of all time. But most shareware games weren't Doom!)
Above all my interest is in the people whose stories get ignored, and the communities that supported them in their work. I wouldn't be interested in making a podcast episode that was a deep dive into the development history of UT2004, and the hype cycle surrounding it on release, but I'd definitely consider talking about the fan community that surrounds it now, keeping it alive long after the industry has moved on, well within the scope of my project.
That said, that's just how I think of it. It's not like anyone else was using this forum for anything, so if you're excited to talk about a thing with the folks here, I'm sure not gonna stop you.