The BlizzardInterfaceCode for QuestUtils.lua is the same for Classic and BCC as of the current releases Classic 1.13.7.38704 and BCC 2.5.1.38988, but it appears that Classic does not have C_TaskQuest which causes calls to QuestUtils_GetQuestName to crash. In BCC it works fine.
Maybe you can just choose to not use it? nothing else is using it in framexml
classic_era is not really in development so I wouldn’t put much hope into it