Its not doing anything special that could "trash" the input. In fact no other env variables are read at all. So the fact that you are seeing your email, is a pretty strong indication that it is being set by you somewhere. Where else could it even get it from?
An other option is that you passed your email as a parameter mistakingly (which takes precedence over the env variable)
But the code is really pretty simple. https://github.com/npiv/chatblade/blob/4ce28739ca7ada1611029...