There are two contexts defined for all pages within the CONTENTdm website, global and collection. The global context applies to the home page, the about page, and the search page when more than one collection is being browsed or searched. The collection landing pages, item pages, and a search page for a single collection have a collection-level context. This context allows you to define customizations that apply only to specific collections. The most common application of this context is defining a custom page header for a collection, but this context can be utilized by any UI customization.
This global vs. collection-level context is sometimes explicit and sometimes implicit. For example, in the Website Configuration Tool there is a separate tab for collections where you can define the header and other settings for each collection. You can also specify whether a specific collection should have a unique identity or setting, or whether it should inherit whatever settings have been specified at the global level.