That is the output of the `ls` command, which lists the contents of a given directory. Each line of the output can be interpreted like a table. In your case there's only one line. We'll take the pieces one at a time:
`-rw-r--r--`
This indicates what the permissions are for the file. The ten characters shown are of the form `drwxrwxrwx`. Each letter means that a certain permission is "on". If a letter is replaced by a hyphen ("-") that means the permission is "off". The first one ("d") just indicates whether the item is a directory (also known as a folder). After that the letters come in three groups of `rwx`. The `r` represents read permission, the `w` write permission, and the `x` execute permission. The three groups themselves are for the file owner, the file owner's group, and finally for all other users.
In this case, `-rw-r--r--` indicates that
- The item is a regular file, not a directory
- The file owner has read and write permission
- The file owner's group has read permission
- All other users have read permission
- The file is not executable
`mykkel`
This is the username of the file owner.
`staff`
This is the file owner's group.
`537M`
This is the size of the file (which is probably what you're interested in). The `M` indicates Megabytes (or possibly Mibibytes, I'm not sure)
`May 11 13:44`
This is the "Last Modified" date of the file.
`iphone_5.5_P3_13.4.1_17E62_Restore.ipsw.download`
This is the filename.
