Create custom layout for ‘core/post-template’ block variation.

Hello,

I’m seeking assistance with creating a variation of the core/post-template block. I recall reading a documentation article on this topic but can’t seem to find it again. Specifically, I remember that to create a custom layout (not ‘flex’, ‘grid’, or ‘constrained’), you need to set the following attribute:

“layout”: { “default”: { “type”: “custom” } }

However, when I did this, my block variation continued to apply some WordPress ‘layout’ classes to the block. I’d like to review the relevant documentation again or see some code examples (e.g., from plugins) that demonstrate how to properly create variations of the core/post-template block with a custom layout.

Thank you for your help!