I’m using Random.Range() without putting a seed. It means that I’m using the built-in seed. Can I know where this seed came from?
Random has a seed (or something like it after unity deprecated Random.seed for some reason).
Check this page.
As an answer to the question: “Can I know where the seed came from”: No. You can’t know for sure. This is handled in Unity’s native code so we can’t simply look it up in their reference github. It is probably set using something ‘random’ like the current time when you start the application. To quote the documentation:
The seed is normally set from some arbitrary value like the system clock before the random number functions are used. This prevents the same run of values from occurring each time a game is played and thus avoids predictable gameplay
The actual value used for initialization might also be platform dependant. As not every platform that Unity builds for might allow you to get the system clock for instance (not in the same way/precision at least).
Also, if you wish to set the seed yourself, you can use Random.InitState as mentioned by others already, it replaces Random.seed which is deprecated.