Use bii open command to use and edit any published block locally.
You can use this command to edit any block you’ve seen on the web and you want to edit.
Just create a new project and once in it, open the block:
$ bii init myproject
$ cd myproject
~/myproject$ bii open USER_NAME/BLOCK_NAME
You can find the block you just opened in the blocks folder within your project.
Take a look at Workflows section to learn how to modifify its source files and publish a new version.
If you are updating or creating a block from another service, check the integration guide to know how to proceed.