Similar to the Gmail Dot feature and the + feature there is one more feature in gmail, where the gmail = googlemail
The Googlemail Feature
Here @googlemail.com is equal to @gmail.com
Which means [email protected] = [email protected]
About this google says
Also, if you’re receiving messages sent to your username @googlemail.com, don’t be concerned. [email protected] is the same as [email protected], too; googlemail.com is Google’s email domain for users in the United Kingdom and Germany, so if you register your username @gmail.com, it becomes unavailable in @googlemail.com as well.
There are multiple uses of this feature some of which I have listed here.