https://www.zsh.org/mla/workers/2022/msg01198.html
Re: UNICODE Private Use Area characters in BUFFER
private use areaunicodecharactersbuffer
https://www.utf8icons.com/subsets/private-use/2300
Private Use Area | UTF-8 Icons
UTF-8 Icons aims to offer it's visitors an easy to use method for identifying those hard to find UTF-8 characters that can be used as icons in place of images.
private use areautficons