Apple officials have not changed the function of Safari's fixed label icon. By default, the label displays the icon of the website or the initials of the website name (if the website does not give an icon).

However, there is a small way to change the text display on a fixed label that displays the initials:

First, please open a fixed tab whose name you want to change. For example, I have a label here that says "B", which is the initials of the website Bitbucket.

Press command+D after opening, and a bookmark window will pop up, as shown below.

Please fill in the letter name you want to display on the icon, and then select "Add". For example, I enter a "z", and then you can see that the letter on the label has changed to the letter you just entered.

If you need to change the display on the label again in the future, just change the name of the bookmark. Names are not limited to English letters, but also Chinese, as shown below:

However, this method is only applicable to labels without website icons, and labels with inherent icons (such as Tencent's labels in the main picture) cannot be changed.