How the safari make sure the little icon on the page be correctly accessed?

i change everything about icon file in my web server but the icon just don't change at all. why? is it about cache problem on the hugo or it is bug on safari?(i have remove cache on the iphone)

I think it's solved, maybe because nginx didn't locate the static directory correctly or it was simply an issue between the https and http protocols.

How the safari make sure the little icon on the page be correctly accessed?
 
 
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