Beginning with Windows 10 (Version 1607), setting LongPathsEnabled to 1 apparently allows to have filenames longer than 255 or 260.
As soon as a process performs a call to a Win32 file or directory function, the set value will be cached on a per process basis. During the lifetime of a process, the value won't be re-read.
The value can also be modified with Group Policy at Computer Configuration -> Administrative Templates -> System -> Filesystem -> Enable NTFS long paths.