This command is a shortcut to JetBrains Rider's code exploration and inspection features:
You can invoke this command from the editor editor, from the Structure window and other tool windows. Depending on the context, this shortcut helps you access all code-exploration features available in that context.
To view contextually available code exploration features
Place the caret on a symbol in the editor editor or select the symbol in the Structure tool window.
The Inspect This drop-down list appears.
Choose an item from the list and click on it or press Enter.