NAME style/path — file system path names
macro can be used for all kinds of path and file names: absolute paths, relative paths, directories, files of all types, including regular files, symbolic links, character and block devices, sockets, and fifos.
If parts of the file name or path are variable, it can even be used for parts of file names. In that case, use Ar
to mark up the placeholders for the variable parts.
The FreeBSD auto_master(5)
manual mentions this class of paths:
.Pa /net/ Ns Ar nfs-server-ip Ns / Ns Ar share-name Ns /
The MACRO REFERENCE section in the mdoc(7)