Fresh install has default gemini homepage of gemini dot circumlunar dot space. Page is loaded every time app is started, and maybe for every new tab opened. There was no opt in, other than app install. This feature was not clear until using app. AFAIK, the only way to have a blank home page is to enter an invalid URL in settings, but this causes “failed host lookup” error page display on start, and DNS traffic.
No disclaimer or opt in type wording in description: https://f-droid.org/en/packages/ca.snoe.deedum/