I created a plugin for all my custom blocks and modifications to default blocks. When I try to extend the default “heading” blueprint in my own blueprint like described in the “Extending Blocks” section in the references, my backend doesn’t load anymore. It gets stuck. The Kirby icon in the top right corner keeps spinning forever.
Thanks for your answer. Sorry! Actually the wrong indentation came from copying the code to the forum. For my blueprint I copied over the original code from the website. Indentation should not be the problem.