In solution explorer you sometime see heart overlay in the class definition nodes. What does it signify?
Solution Explorer is a special window that enables you to manage solutions, projects, and files. It provides a complete view of the files in a project, and it enables you to add or remove files and to organize files into subfolders.
I believe you are referring to a signal icon. The heart is shown over types / members when they are internal (C#) or Friend (VB.NET). The meaning of the icons is documented on Microsoft Docs:
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