What is a system block?

A system block will, in most cases, rely on the existence of other content you've created in order to make the system block work.

Let's take an example of the Slideshow Gallery Block. This block will request that you enter the name of a photo gallery album you've already created. You can place the block anywhere in your site, but if no images are present in the connected gallery, nothing will display in your slideshow. 

System blocks can ask for configuration options.

The RSS Feed block will ask you for an external feed URL, for example. The majority of blocks will let you choose a column width for its configuration display. Some will allow for branding options.

In all cases, the system blocks can be located through any of these three routes:

1. Manage » Structure » Block layout page » Place block button, or;
2. Shortcuts » Blocks » Place block button

The Place Block button is your path to accessing the list of available system configuration blocks. With exception of Chaos tools and Core options under the Category section, all the rest are available to use as system blocks.

The Category information will indicate the nature of the block. With the exception of the Core or Chaos Tools types, the rest of the blocks are available to use provided that the required affiliated content already exists.