What is this icon on the status bar that looks like a cracked egg? (see screenshot) I'm using Samsung Galaxy Note 5 on Android Marshmallow. I was just wondering what that oval-shaped symbol near the top center was.
According to a mod to remove the icon on XDA Forum, it's RCS Service.
According to GSM Association (GSMA), the one behind the development of RCS technology,

What is RCS?
Rich Communications Services (RCS) is the platform that enables delivery of communication experiences beyond voice and SMS. It provides consumers with instant messaging or chat, one to one or to groups, live video and file sharing across devices on any network.
RCS marks the transition of messaging and voice capabilities from Circuit Switched technology to an all-IP world. It shares the same IMS investment and leverages the same IMS capabilities as VoLTE and video calls over LTE.