All confusion aside - the point of the log is to paste as a message on these forums, so I don't know offhand what program would open it.
It uses [ ] as tags, which I think are basically only used for forum code.
If you want to see them with colour etc. then copy them as a message here and hit preview.
Edit: I just downloaded it, and yea - Beef already said it but:
"You can select what type of tags (<HTML>, [forum], none) for simple pre-formatting in the "style" variable in autolog.py. Also, you can change whether or not forum-style notes are color-coded in the "color" variable in autolog.py."
That's in the readme - if you want to read it with notepad you may want to change it to none.