How to hide bookmarks toolbar icons in Firefox (v106, 2022) on macOS

Add:

@-moz-document url(chrome://browser/content/browser.xhtml){
	#personal-bookmarks .bookmark-item:not([container]) .toolbarbutton-icon {
		display: none !important;
	}
}

To: 

/Users//Library/Application Support/Firefox/Profiles/xxxxxxxx.dev-edition-default/chrome/userChrome.css