The /mnt directory is the customary mounting point for temporarily mounted filesystems in . It is an empty directory, and the intent is that if you have to, for instance, mount a floppy, you can use /mnt as its mount point and don't have to create a new directory each time. It is just for convenience, no programs contain embedded information about /mnt . Some people call their /mnt
something else, such as /floppy . Others prefer to have subdirectories below /mnt , so that they can have several mount points, e.g. /mnt/a for the first floppy drive, or /mnt/dos for the MS-DOS hard disk partition.
The /swap directory is similarly only a commonly used mount point. As the name implies, it is intended as the mount point for the swap partition.