Entities that have the field "master"

What exactly does it mean when an entity has the field labeled "master"? And in what situations would the master field be used? Thanks.

From how I understand it, the "master" field implies that the entity won't function without a active multisource as it's "master". (As far as I know, multisources are the only entity that can function as a master) This is useful for locked doors/buttons/other interact-able objects. Think of it like the first entity is the "slave" to the multisource and can't do anything without it's master's permission.

There could be more to it but this is as far as my knowledge goes.

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Now remember kids. Asking questions is a good way to get censored by the government.

Thanks. It makes more sense now.