With MobileFrontend installed applying
?useskin=vector&useformat=mobile will ensure that responsive vector
mode is invoked.
I'm keen to do this, as it would help to have more examples of skins
that are MobileFrontend aware as part of the work I am doing in
T166748
Change-Id: I81edd855a5e96400d1179fb10907fcc30ea43ef7