Against current master with $wgMFAutodetectMobileView = true in LocalSettings, I get a fatal error when trying to load my local site in a state that should induce the mobile view:

Original exception: [f2672a8a] /testing/core/index.php/Main_Page Exception from line 201 of /mnt/hgfs/wikimedia_git/extensions/MobileFrontend/includes/DeviceDetection.php: PredefinedDeviceProperties::isTablet() called!
Backtrace:
#0 /mnt/hgfs/wikimedia_git/extensions/MobileFrontend/includes/MobileContext.php(133): PredefinedDeviceProperties->isTablet()
#1 /mnt/hgfs/wikimedia_git/extensions/MobileFrontend/includes/MobileContext.php(361): MobileContext->isMobileDevice()
#2 /mnt/hgfs/wikimedia_git/extensions/MobileFrontend/includes/MobileContext.php(279): MobileContext->shouldDisplayMobileViewInternal()
#3 /mnt/hgfs/wikimedia_git/extensions/MobileFrontend/includes/MobileFrontend.hooks.php(785): MobileContext->shouldDisplayMobileView()
#4 [internal function]: MobileFrontendHooks::onOutputPageParserOutput(OutputPage, ParserOutput)
#5 /mnt/hgfs/testing/core/includes/Hooks.php(206): call_user_func_array(string, array)
#6 /mnt/hgfs/testing/core/includes/GlobalFunctions.php(4008): Hooks::run(string, array, NULL)
#7 /mnt/hgfs/testing/core/includes/OutputPage.php(1605): wfRunHooks(string, array)
#8 /mnt/hgfs/testing/core/includes/OutputPage.php(1614): OutputPage->addParserOutputNoText(ParserOutput)
#9 /mnt/hgfs/testing/core/includes/Article.php(630): OutputPage->addParserOutput(ParserOutput)
#10 /mnt/hgfs/testing/core/includes/actions/ViewAction.php(44): Article->view()
#11 /mnt/hgfs/testing/core/includes/Wiki.php(428): ViewAction->show()
#12 /mnt/hgfs/testing/core/includes/Wiki.php(292): MediaWiki->performAction(Article, Title)
#13 /mnt/hgfs/testing/core/includes/Wiki.php(586): MediaWiki->performRequest()
#14 /mnt/hgfs/testing/core/includes/Wiki.php(447): MediaWiki->main()
#15 /mnt/hgfs/testing/core/index.php(49): MediaWiki->run()
#16 {main}

Version: unspecified
Severity: normal