Ion_auth: How to determine installed version?

I installed the ion_auth library some time ago. How can I determine what version it is?

The current version available for download appears to be 2.6.0. This is indicated by the filename of the "download" link at ion_auth site (https://github.com/benedmunds/CodeIgniter-Ion-Auth). However, the version history is not listed on the site.

Usually, at the start of every script file you'll find a commented block, which has the description, developer, and version of it. Open the libary and read the begining of it.