Should a phonegap plugin be declared in the config.xml file?

Question

I am a newbie in phonegap development so I have a couple of questions:

1) I am using the accelerometer plug-in. I read in the manual that i need to declare the plugi

Answer 1

Since cordova 3.5, we can persist plugins in config.xml file

The following command will fetch the plugins defined in config.xml

cordova restore plugins --experimental

The following command will write your current installed plugins in config.xml (3.5):

cordova save plugins --experimental

In 5.x and later:

cordova plugin save

Source: http://cordova.apache.org/news/2014/07/10/tools-release.html