How do lightgbm encode categorial features?

I have the following structure of one lightGbm tree: {'split_index': 0, 'split_feature': 41, 'split_gain': 97.25859832763672, 'threshold': '3||4||8', 'decision_type': '==', 'default_left': False, 'missing_type': 'None', 'internal_value': 0, 'internal_weight': 0, 'internal_count': 73194, 'left_child': {'split_index': 1, and the feature in 0 node is categorial and I feed this feature in format "category". where can I find the appropriate between number format and category?