Recommended further modification: SSH public key file's comment

At the end of the public key, a comment may be specified. It is recommended that the optionalComment contain some sort of identifier (such as a filename) that specifies which private key is expected to be used with that public key. Such details are easy to forget over time, particularly after a person uses multiple keys (perhaps after working on multiple computers).

A person might wonder why it is helpful to put the filename into the file. After all, the filename is needed in order to see the contents of the file, so presumably one already knows the filename if the file is being looked at, right? Well, the reason is that there is a common practice of copying the contents of an SSH key into another file named authorized_keys. If that is done, then the filename of the public key is not necessarily going to be retained near the key data. Later on, when viewing the authorized_keys file, it can be nice to see that comment. Furthermore, sometimes people will do this process multiple times for a single public key file. So, placing the information here now, once, is less work than trying to remember to copy the filename each and every time.