The uri can be the relative path [PACKAGE_NAME]:[RELATIVE_PATH] or the alias @[ALIAS_NAME].
FCF relative paths:
PACKAGE_NAME - the name of the package in which the file or resource is located. If the path refers to the root of the application, then the PACKAGE_NAME parameter is not specified, and the first character is :.
RELATIVE_PATH - the relative path from the root of the package or application.
ALIAS_NAME - an alias name that can be set or overridden in the application or package configuration via the aliases parameter. Aliases always start with the @ symbol.
true - the path is returned in the context of the server file system
false - the path is returned in the context of the relative path of the browser
If the value is not specified, then if the code is executed on the server side, the parameter is true, and if the code is executed on the browser side, it is false.