If the custom page path includes optional or required keywords (!keyword or %keyword, respectively), Page manager can use the values provided in the path to load contextual objects (covered later on in this book). A click on the change button at context assigned opens a dialogue where you can specify how Page manager should interpret the provided path argument. In most cases, the path arguments are numeric IDs used to load the corresponding node, user or taxonomy term, but other options are available, too. You are also provided an opportunity to give an administrative name (context identifier) for the object loaded from the path argument.
If for some reason you don’t want to load any contextual object with the path argument, choose no context assigned.
Figure 13.3: If the custom page path contains dynamic parts, arguments, Page manager may use the provided values to load data.
How can this be used?
Keywords in a path user/%account/message/%friend can be used to load two separate user accounts, with IDs corresponding to %account and %friend. These could then be used (with Views) to list nodes written by %account and addressed to %friend.
The keyword in the path replies/%comment could be used to load the comment with ID %comment, and (with Views) list all comments posted as a reply to that comment.