I have always needed to add some string to an existing url which is set manually.
For example i have content type case study
and I want the url to be
Where case study is always the same , but the second part is set manually for each node.
the functionality is similar to the token in Page titles called "current title"
When creating the node the node url can be set as required (so that the current-url token is not empty) or generated from the node title if missing.