What does the square symbol means in pm2?

Question

It is confusing for me to get the meaning of the symbol when I run the below command:

pm2 status

It shows a table. The confusing part is the square symbol which I have marked in the below picture

What does it actually mean? Are three instances of index server running or something like that?

Answer 1

Quoting @Flimzy comment:

That looks like the Unicode replacement symbol, indicating your terminal cannot display the proper character there.This doc shows an arrow in a similar looking column.

This column/value refer to the process's number of restarts which have occurred since the first run.

To see it in actions, the following command does restart the process pm2 restart <process-name|id>, which will increase the restarts counter by 1.