Please use more direct correspondences with desktop.

For instance, when a wiki sets createaccount $wgGroupPermissions false,
createacct-benefit-heading will never be seen, as it only appears on
Special:UserLogin&type=signup when createaccount permission is true.

Instead on MobileFrontend it appears regardless, on Special:UserLogin
itself.

Also one cannot make

function JidanniLoginFormMessage(&$template){global $wgSitename; $template->set( 'header',
"（需帳號來編輯者，請聯絡<a href=\"/index.php?title=User:WikiSysop\"><strong>${wgSitename}</strong>管理員</a>，"
    . "告知欲立帳名，直接用中文姓名亦可。）");
    return true;}

appear on MobileFrontend's Special:UserLogin, despite trying

$wgHooks['UserLoginForm'][]=$wgHooks['MobileFrontendHooks::onUserLoginForm'][]='JidanniLoginFormMessage';

although it appears fine on desktop.