What does the number after the word spinfile in macro variable?

cnhx

Excuse me, I'm newbie with GSA SER script engine.
In some .dat files, I notice macro variables of type %spinfile9-xxxxx.dat% (eg. %spinfile2-months.dat%)
What does the number after the word spinfile?

Sven

There are just %spinfile% and %spinfile2%. The %spinfile2% macro behaves like the other except that it does not keep in mind the previous chosen value.