Golang variable declaration syntax meaning : <p>I am going through some Golang code and came through this block of code, I am not able to comprehend it. I can see that d1,d2,d3 are variables of type int. But what is the last string <code>json:"start"</code></p>

<pre><code>type obj1 struct {
    d1   int `json:"start"`
    d2     int `json:"end"`
    d3 int   `json:"retries"`
}
</code></pre>
