They might be "hiding" the setting by not including it in the main settings page, but there is no other (mainstream) browser with anything close to the equivalent of the flexibility of about:config.
Though judging by the logic espoused in the tab-close-button bug step one is to move it to about:config and then step two is removing it all together for not being discoverable enough.
yes, but they also change about:config "Preference Names" possibly to confuse users so that they stop messing with settings? for example the preference name for the number of lines scrolled when using the mousewheel used to be "mousewheel.withnokey.numlines", I believe it is now "mousewheel.acceleration.factor" ... I didn't keep track of all the changes, but I am sure that there is many others.
