Your username is used to construct your "host mask", which is a string representing you. It includes your connection's host name and this username. It is sometimes used for setting auto-op, bans, and other things specific to one person.
您的用户名用于构建您的“主机掩码”，这是一个代表您的字符串。它包括您的连接的主机名和此用户名。它有时用于设置自动操作、禁令和其他特定于一个人的事情。