I am currently digging through the Google IO 2019 source code and there is one thing I can't figure out where it comes from: the color of the hamburger menu icon.

Here's a screenshot of the preview of `mobile\src\main\res\layout\fragment_codelabs.xml` ([source link](https://github.com/google/iosched/blob/master/mobile/src/main/res/layout/fragment_codelabs.xml)):
[![enter image description here](https://i.stack.imgur.com/B0R50.png)](https://i.stack.imgur.com/B0R50.png)

And here is a zoom-in of the hamburger menu icon, one can easily see that it's at least not black:
[![enter image description here](https://i.stack.imgur.com/QEuFi.png)](https://i.stack.imgur.com/QEuFi.png)

The image source is `@drawable/ic_menu`:
[![enter image description here](https://i.stack.imgur.com/XzJau.png)](https://i.stack.imgur.com/XzJau.png)

The source code of `@drawable/ic_menu`(`mobile\src\main\res\drawable\ic_menu.xml`) ([source link](https://github.com/google/iosched/blob/master/mobile/src/main/res/drawable/ic_menu.xml)) is 

```
<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:width="24dp"
    android:height="24dp"
    android:viewportWidth="24.0"
    android:viewportHeight="24.0"
    android:tint="?colorControlNormal">
    <path
        android:fillColor="#FF000000"
        android:pathData="M3,18h18v-2L3,16v2zM3,13h18v-2L3,11v2zM3,6v2h18L21,6L3,6z" />
</vector>

```

So here the `fillColor` is specified as `#FF000000` which is 100 % black and opaque (alpha FF). Yet the hamburger menu icon isn't displayed in black. So, where is the color that the hamburger menu icon is displayed in actually coming from?