On the Artifacts tab of the release definition editor I can choose as artifacts source type the "Team Foundation Version Control" in the Link an artifact source pop-up.
According with the documentation it's possible to specify a certain changeset to be used as a source:
When you link a TFVC branch, you can specify the changeset to be deployed when creating a release.
But in the editor is possible to select only the root (e.g. $/FooBarProject).
How can I specify to download only a specific changeset? I don't need to download the entire repository when I need just one script.
TFS Version 15.112.26301.0
When you specify a changeset, you're specifying a specific changeset for the entire repository. There's no way to conditionally restrict it to just the contents of that changeset.
If you need a specific file or subset of files, you should publish it as a build artifact.