I sent this question to support over at Modern Tribe and they responded with this
My question: 1) I have set the page for my main calendar to be “Calendar” but the page title is saying “Events”. I have a separate page for events and would like the title to say “Calendar”. Their Response: Took a look at your website and looks like this title is generated by GeneratePress, your theme. Probably you have some place to edit this, but I can’t tell you exactly where are this.