Additional length on email body

I want to see the full email that is being sent to Pushover. For example, I need to unsubscribe from a vendor's marketing emails, but cannot do so currently because only so much text comes through the app, thus cutting off the unsubscribe link.

Unfortunately with this vendor, their marketing emails automatically match the user's email, which is what their notifications are based on...which is my pushover alias. While I hear an alert that one of my servers is down, it may just be a marketing email about their Super Bowl ad.

I can't find any literature about the current character limit for emails.