What method did you previously use or did you do this in Firefox 56 via a Legacy extension ?

In current releases you would have to use code in userChrome.css to hide the favicon on the Bookmarks Toolbar.

#personal-bookmarks .bookmark-item:not([container]) .toolbarbutton-icon {
 display: none !important;
}

More info about userContent.css and userChrome.css in case you are not familiar: *https://www.userchrome.org/what-is-userchrome-css.html

• https://www.userchrome.org/how-create-userchrome-css.html

i have used that exact code in regular firefox and waterefox and it woprked but not in Developers Edition...i just deleted and recreated the userChrome.css file, entered the code again but the favicons are still there

In Firefox 69 and later you need to set this pref to true on the about:config page to enable userChrome.css and userContent.css in the chrome folder.

• about:config => toolkit.legacyUserProfileCustomizations.stylesheets = true
• https://www.userchrome.org/firefox-changes-userchrome-css.html

set to true in about:config -> toolkit.legacyUserProfileCustomizations.stylesheets

that did it...thank you very much