The whole composer has been refactored recently and we have decided to move the "generally less used buttons" in the dropdown.
This is because often on mobile devices there is always some display problem or trouble tapping the right button when there are too many buttons and too little space between them. Consider that many sites, unlike Arduino, often install or activate plugins or official components add extra buttons to the composer. See as example our composer on Meta, where we only use a few plugins which also add functionality to the composer:
VS Arduino composer which is the basic one with no extra buttons
Most likely the next step will be to let the admin decide, via site settings, which buttons to leave visible and which buttons to put in the dropdown