Where all are the hooks defined in a contributed module? What are the files in which core hooks are implemented in a contributed module?
Are they declared in .inc files? If so, what are the naming conventions for those include files containing core hooks?
The convention is to park all core hook implementations in .module.
.inc files are used to break off different groups of code like custom class definitions &amp; administration form handlers. Some have their own naming convention for contrib hook implementations (e.g. .views.inc, .rules.inc, etc.).