Where is adb located when installing Unity and Android SDK for Mac?

I'm getting Android Build Failures and would like to locate adb to do some queries like adb devices but where is adb installed? I've already installed the Android SDK for Unity.


From @Programmer's answer, this line is no longer true:

You are responsible for downloading, installing and setting up Android SDK and then manually setting the paths in Unity.

Unity now allows and encourages you to install the Android SDK via their Unity Hub:

Use the Unity Hub to install Android Build Support and the required Android SDK & NDK tools: enter image description here

From the same page, I found adb.exe is located at: /c/Program Files/Unity/Hub/Editor/2019.2.1f1/Editor/Data/PlaybackEngines/AndroidPlayer/SDK/platform-tools/adb.exe