Data Type Text (text field: A type of field whose content is text. Examples include the Task Name and Email Address fields. This field can contain up to 255 characters.)
Entry Type Entered (entered field: A field in which you may type or edit information. This is in contrast with a calculated field, in which Project calculates and enters information.)
Description The Subproject File field contains the name of a project inserted into the active project file. The Subproject File field contains the inserted project's path (path: A sequence of all folder names from the root to a file's current folder, separated by backslash characters [\] in Windows.) and file name.
Best Uses Add the Subproject File field to a task sheet when you want to display, sort, filter, or edit the names and paths of outside projects that are the source of the task. This is particularly helpful when you are working with multiple projects in one window. This is also helpful when you need to distinguish among tasks between one inserted project and another. You can also type the name of another project in this field when you want to insert it into the active project file.
Example Your project contains three inserted projects (subproject: A project that is inserted into another project. Use subprojects as a way to break complex projects into more manageable parts. Also known as an inserted project.). As you work with tasks and adjust the schedule, you want to see the names of the inserted project from which the tasks originate. You add the Subproject File field to the Task Sheet view.