My copy of IntelliJ just shows CSV files. I've also got a menu entry Settings -> Tools -> CSV Formats. However, I don't know if that's built into IntelliJ or if it's from a plugin. If it's the latter, then it could be the Python plugin.
It would be good if IntelliJ had a way of telling which plugin some feature comes from, because some settings from plugins are dropped into the top level without any indication of where they've come from.