This question already has an answer here:
In version 10 some built-in symbols are updated to support operator form like the
Derivative. For example,
Map-related functions, and so on. These updates are handy (although it is not clear whether they are directly defined as
SubValues for the symbols or defined as functions, see this answer.)
In principle we can check all the new symbols listed here to see which of them have operator form. But this is tedious. Is there a way to automatically return such symbols from
Names["System`*"]? The difficulty is, neither
SubValues can be used to built-in symbols to return useful information.