UPDATE How to remove the Extensions button in Firefox 111

Mozilla recently released Firefox version 111:  What's new in Mozilla Firefox 111 | N... that removed the options previously described to remove the extensions button. Now as posted by Techdows: https://techdows.com/2023/03/remove-e..., it is once again possible to disable the extensions button in version 111. If you would like to remove it, here's how.
toolkit.legacyUserProfileCustomizations.stylesheets

#unified-extensions-button{width: 3px;
padding-inline: 0 !important
}
#unified-extensions-button  .toolbarbutton-icon {
width: 0 !important;
}

userchrome.css

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