What is the 'combustion point' of a game? This was in an upvoted answer Saw an answer and it had been upvoted. 
Person answering had a large rep on stack.

The term used that was not explained is: 
'Combustion Point' (of a game)

My question is just what does 'combustion point' of a game mean?

Intuitively to a native speaker it would seem to mean something major like a disaster happened.  That does not seem to fit as it was applied to all games around move 26 per the OP it answered.
The question you mention is here: In ChessBase 12, when viewing an Opening Tree, why do all the games always stop near move 26?

Personally, I think it is just a general English statement he used to describe the middle, and most heated analytically, part of the game based on the context. I doubt anyone else would repeat it.

Frankly, if I downvoted a lot, I would probably have downvoted that answer since it does not really begin to answer the question. The real answer is either the user was doing something wrong, and should have been shown how to do it (probably not), or simply that was the way it was in the code because that is where they arbitrarily cut off the opening, and cannot be changed (probably).

P.S. If I were to ever describe a part of a chess game as such, it would be where everything came to a head, and the tactics started to fly.