Board Thread:Support Requests - Designing Your Wiki/@comment-5745743-20180721004722/@comment-27345308-20180721132250

Only limitations placed on customizing rail are by customization policy, but it doesn't really specify what kind of changes are disallowed. In general, I'd say you shouldn't change their look too much and don't touch the Trending FANDOM Articles module at all. If you want to add additional custom modules, there's AddRailModule for that. What specifically do you want to customize in them?