With elm-pages, we get nicely typed RouteParams based on which of these we use. We have to use a different naming convention because Elm modules must start with a capital letter, followed by alphanumeric or _ characters. page 
# RouteParam Field Normalization
If RouteParams has a field which cannot be turned directly into a valid Elm field name, it can either be normalized, or the framework could give an error.
[…] Adding an underscore in these cases is sufficient for reserved words. I think it makes sense to just normalize them, since each route parameter should have a unique name so we shouldn't need to worry about collisions. […]