Strange daily peaks in the number of requests to images???

[indus]

I just noticed something strange. The number of requests to the favicon of js.org start to rise every day at exactly 4pm (UTC+1) and drops back to a baseline at 10pm:

favicon.ico, apple-touch-icon.png and other similar "images" show the same behaviour but no other resources (HTML, JS, fonts).
The spikes match the number of requests from Russia:

I can't see an obvious reason for this. Does anybody have an explanation?

The subdomains look normal:

[Rishav-02]

Wow nice statistical data @indus