Why do we have a database specification in .pgpass?

We have a database specification in .pgpass:
hostname:port:database:username:password

What is the purpose of 'database' since username/password combinations
are global, not per database?  I would like to documents its purpose.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +