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In some of Valve's games where the Source Engine is used, they do not use entity names for playermodels as it would cause problems having to specify every name of the actors from map editors. Valve solved this problem up by using global actors that is capable of "detecting" models for the specific actor.
This is used in features like Response Rules, for example, the Citizens have their genders specified in the global_actors.txt to make them play their responses specific to the gender ($gender is used here for the soundscripts, it can detect the models if they are marked as either "male" or "female", restricting the specified model to only play the sounds and responses specific to that gender). When done, it prevents having to make seperate soundscripts for both genders.
However, if, for example, a model that has no name specified (no "female" or male"), when used as the entity npc_citizen, they will randomly play the responses of the two genders because they lack it.