During the sanctions, it was noted that Huawei had been working on its own in-house operating system codenamed "HongMeng OS": in an interview with "Die Welt", executive Richard Yu stated that an in-house OS could be used as a "plan B" if it were prevented from using Android or Windows as the result of U.S. action. Huawei filed trademarks for the names "Ark", "Ark OS", and "Harmony" in Europe, which were speculated to be connected to this OS. On 9 August 2019, Huawei officially unveiled Harmony OS at its inaugural developers' conference in Dongguan with the ARK compiler which can be used to port Android APK packages to the OS.