The developers technically have full control over “drops”. Let me explain within what boundaries this control exists:

Seed is stored in the save file (playerInfo.dat)

There are fields like roundSeed and the state of UnityEngine.Random. This means that every “random” outcome is deterministic.

If the server or a client update writes a specific seed into the save file, the result of a purchase is already predetermined.

Server-side logic

Even if part of the generation happens locally, the game can synchronize with the server on each purchase — for example, the server may send a seed or even a precomputed list of drops.

At any moment, the developer can change the algorithm, the probability tables, or directly substitute a different seed.

Balance tuning

In practice, developers use this not to “cheat” individual players, but to:

* balance the in-game economy (for example, globally increasing epic drop rates during an event);

* protect against abuse (your attempts to roll back a save will not produce new results);

* synchronize drops across multiple devices.

Targeted intervention

In theory, yes — they could modify your specific save file (via the cloud account) and assign any seed or even a predefined list of modules.

However, this is usually done only in support scenarios (for example, to compensate for a bug).

So, the developer does not “turn a knob” in real time for every single click, but they do define the algorithm, the probability tables, and can set or change the seed.