A Gst::Element can have several properties which are implemented using standard GLib::Object properties. The usual GLib::Object methods to query, set and get property values and GLib::ParamSpecs? are therefore supported.
Every Gst::Element inherits at least one property of its parent Gst::Object: the "name" property. This is the name you provide to the methods Gst::ElementFactory.make or Gst::ElementFactory#create. You can get and set this property using the methods Gst::Object#set_name, Gst::Object#name= and Gst::Object#name.
Most plugins provide additional properties to provide more information about their configuration or to configure the element.
gst-inspect is a useful tool to query the properties of a particular element, it will also use property introspection to give a short explanation about the function of the property and about the parameter types and ranges it supports.