For me the function "Clear History..." and selecting "all history" in Safari 14.0.3 (Big Sur) clears the complete favicon cache in ~/Library/Safari/Favicon Cache/
With Safari on iOS on the other hand there appears to be no way to clear the cache short of factory resetting.
For me the function "Clear History..." and selecting "all history" in Safari 14.0.3 (Big Sur) clears the complete favicon cache in ~/Library/Safari/Favicon Cache/
With Safari on iOS on the other hand there appears to be no way to clear the cache short of factory resetting.