macOS / OS X ships with the ability to mount volumes via AFP. However, OS X 10.6 and newer are not capable of AFP version 2.x or older which is needed to network with Classic MacOS (7.6 to 9.2 via IP).
This version of afpfs-ng is based on Simon Vetter's version. It has fixes 'hacked in' to make it work with Fuse for macOS / OSXFUSE on macOS / OS X. As a consequence, it does not work with Fuse for Linux.
It is of use for you if you emulate Classic MacOS, e.g. using SheepShaver or QEMU. And of course if you own an old Macintosh you want to exchange files with.
macOS / OS X already makes use of the 'mount_afp' command. Thus in this version of afpfs-ng that command has been changed to 'mount_afp2' (to indicate it is for use with AFP v. 2.x).
Information on the background and process of porting afpfs-ng to macOS / OS X can be found at http://emaculation.com/forum/viewtopic.php?f=34&p=57993#p57806 . Feel free to join the forum!