I wanted to update this.
I took the time last night to fully read through kernelinfo.txt. It appears to be a dumpstate/logcat from the date I suddenly lost all the remaining freespace on my internal storage. I have another log, anr_history.txt growing out of control (I know why, I traced that to a hanging app). Part of kernelinfo, in fact the majority of it, is a copy of the text in anr_history. I think it actually ran out of room when it created the file.
I'm still curious to know what conditions would prompt android to create that log. It doesn't appear that it's cumulative, but rather overwritten each time it's created (I'm guessing as there's only one header).
Anyone know?