Wasn't AISLE only able to find the same bugs when it was shown only the known faulty code? The worrying part about Mythos isn't the fact that it can find bugs. The worrying part is Mythos being able to find them on its own across entire code base as vast as Firefox then write exploits for what its found with a very basic prompt.
The skill required to find then create zero days is quickly approaching the floor.
I think they split the codebase in smaller files or modules and then tell the AI there's a bug in this particular file and to go find it.
Then they loop over a codebase like this. This way you always point a model at a 'known' bug. And I assume a smaller context window helps with quality.
Not entirely sure it's obviously proprietary.