Moodle version
From MoodleDocs
Often one sees references to differences in different Moodle versions. How can one see which version is on a certain site?
On many Moodle sites (it depends on the how customised the theme is) you can hover the mouse over the Moodle logo at the bottom of the page and you'll see the exact release version.
On all sites you can log in as an administrator and see the exact version at the bottom of the main admin screen.