Understanding Saleor Mutations: Where's the Code?

[Muhammedaashique]

When I first started using the Saleor backend, I noticed something interesting. For example, when creating an account, we use a query like this:
mutation {
accountRegister(
input: {
email: "customer@example.com"
password: "secret@123"
channel: "default-channel",
redirectUrl: "http://localhost:4000",
referalId: "23211"
}
) {
errors {
field
code
}
user {
email
isActive
isConfirmed
}
}
}
In this example, the mutation name is accountRegister. However, I couldn't find the code for this mutation in the backend files, except for a test file. I'm curious, where is the actual code for these mutations written, and if possible, could you explain the overall workflow of Saleor?