24 Ranges library [ranges]

24.7 Range adaptors [range.adaptors]

24.7.8 Drop view [range.drop]

24.7.8.3 views​::​drop [range.drop.adaptor]

The name views​::​drop denotes a range adaptor object ([range.adaptor.object]).
For some subexpressions E and F, the expression views​::​drop(E, F) is expression-equivalent to drop_­view{E, F}.