A single dot (.) means current dir, while a double dot (..) means the parent dir.
However, a / at the begining of the directory means start from the loweset level, and is used for absolute paths.
Seeing as the script requires a relative path from the bots dir, you can't start it /.
It states it needs the / to remain.
As the logs are stored in the bots dir, this doesn't need a value, but it still requires the /. As noted, not possible.
So you tell it to stay int eh current dir with the single dot, and then add the slash.
It may also be a case, that you can even set this to "" (blank), but there is no gurentee without looking at the code, if it supports this. So sticking to the layed out format is the way to go.