When I create a deployment package `web.config` is changed, but I don't understand this part:

I have two `web.config` transformation files, `web.debug.config` and `web.release.config`.

Are these transformation files only available or working when we make a web deployment or make a deployment package? Are the `web.config` transformations not used when the project runs locally from visual studio (e.g. via IIS Express)?