What does 'Last updated' below category mean ?

If we check any category, we can see "Last update xxxxxxxx" on very extreme end of the page. Can any Editor focus light on it ?
What does it acually mean ?

I am very excited to know and to learn about this because many categories were Last updated more than 2 years agon. Does it mean that the Editor(s) of that category hasn't included any site from last 2 years ? or does it mean that no NEW category was added neither any category was modified ?

The last update date at the foot of a public page used to define when an editor last amended the category itself (not including subcategories). Pay no attention to it because for the last couple of years it has usually been incorrect. AOL developers are aware of the bug and will no doubt fix it in time.

Okay. Thanks for reply.