PSA: Time is nearly up for XKit 5!
Nope, that bar that appeared on top of your dashboard urging you to upgrade to XKit 6 was not a virus or anything, but a reminder that XKit 5 has been discontinued.
The ability to download XKit 5 has been discontinued a month ago, and now the Extension Gallery for all XKit 5 users (except for ones on Safari) has been disabled.
On 15th of October, all existing XKit 5 installations will stop functioning. So please upgrade to XKit 6 Today.