How to create a shape？

[hyzx86]

I want to implement a version comparison module。
I looked at the ViewAsJson module code, hope can refer to its part of the code to achieve this function.
However, an exception was reported during implementation
The error message tells me that I cannot find the Shape.
Exception: Shape type 'VersionCompare_Button_Actions' not found

My code:
I think the shape name must same as the template file prefix.

OrcharCore Code:
But it doesn't look that way in this module. They're different, and there's no discerning pattern

Not sure how this shape declaration works.
Or did I miss something?

The document only explains how to use existing shapes, but does not find how to define a Shape.
https://docs.orchardcore.net/en/dev/docs/reference/core/Placement/#what-is-a-shape

[hyzx86]

It works.
When I changed the name to "VersionCompare_SummaryAdmin__Button__Actions".

[hyzx86]

well.. I found that this functionality is already well implemented in the Audit Trail module.