Hello Grzegorz,
You can find the
Site Details tab at the bottom of the comment textarea (see the attached screenshot).
The information you enter there is private, meaning that only I can see it.
Regarding the issue with the icons - you have either figured it out or it is an issue caused by your local environment (browser extensions, cache and cookies, ad blockers, ISP configuration, firewall, etc).
I am not able to reproduce the issue. Here, have a look at
this video that I recorded for you.
For test purpose you might try on another computer.