`SITE_ID` is always defined in settings, and the domain and name will be set via django admin. `SITE_ID` can always be changed in in `local_settings.py`, in a multi site environment where each site have their own settings file, but share the same database, then `SITE_ID = 2`, might have a different name and domain all together using the same codebase and database. One reason I have this piece of code after `local_settings.py` import. Someone can always add the lines in their custom settings file with real paths that may not be the same as the `site_name`, the whole idea was to try to make this a little bit generic and especially for those using `formhub.settings`