Deleting Assets is incorrect because it is as good as removing an integral part of your animation. Instead, the best thing to do is to convert the shape to layers first. This will help you avoid exporting it with JSON.
Assets in animation are basic visual and audial elements and accessories that are used during the modeling of video games, creation of apps interfaces, and animated clips.
They are basically items that fill in the non-active surroundings. Examples are:
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