A manifest file is generated when replacements have been made. This work is saved within the manifest file. If a user however prefers, this manifest doesn't have to be written. Instead, a manifest could be output to standard output.

This would give the developer the option to redirect the output elsewhere (say, >/dev/null) In some cases this is desired, say on a build server, or in a git versioned repo, there is no reason to keep a manifest since each deploys a copy of the original is retained from the source control.