this code is written by Seblod into the Joomla article to be able to be managed as a Seblod type, you do not have to delete it if you want to use the item in Seblod. Probably you edited your article as a Joomla article (Legacy edit) and not as a Seblod item: Seblod automatically hide this code when shows the article as a Seblod item.
cheers