Custom block not showing up in block selection panel

[kavinvalli]

Hi, I just tried setting this up, and ran into an issue. The custom example-file-block isn't showing up on the Block selection panel on the top left.

My URL seems to be right : https://blocks.githubnext.com/githubnext/blocks/blob/main/README.md?devServer=http%3A%2F%2Flocalhost%3A4000%2F&blockKey=githubnext__blocks-examples__markdown-block