In 2.5.8, which part of the code popup the right bottom corner window?

Spark Spark Support
1

I have downloaded the spark 2.5.8 source code from http://svn.igniterealtime.org/svn/repos/spark/tags/spark_2_5_8

Can someone tell me that which part of the code that generates this popup window on the right bottom corner of the screen?

The snapshot is uploaded as Attach File. (spark.bmp)

Thanks in advance!!!