cocos2d-x js 3.0 rc0 cocosbuilder labelttf convert to label

my ccb file consists of labelttf, i was use cocos2d-x js 3.0 alpha. but when i upgrade engine to cocos2d-x js 3.0 rc0, after i load ccb file, i found that labelttf are converted to label. why?

Because labelTTF, LabelAtlas, LabelBMFont are merged in Label at -x v3.0.