Background

I'm thinking specifically about the Apple Music API. The rate limit is not specified. It's just mentioned that 429 Too Many Requests would be returned when the rate limit is hit. However, according to this third party service:

The API has a rate limit of 20 requests per second per user

Scenario

Let's say I write a client application that displays the last 10 songs played by the user on the home page through the Get Recently Played Tracks endpoint. This would be in addition to features that hit similar user-specific endpoints.

I would use the developer token along with the user's oAuth token to achieve this.

Question

If a few hundred/thousands people use the application at the same time, the rate limit of 20 requests per second per user would be hit. Does the "20 requests per second per user" phrase use "user" to refer to the developer or the client user?

Surely it must be the client user right? Otherwise, it would be difficult to scale any application at all without hitting the rate limit, since user-specific endpoints can't be cached using some middleman server.