I made a [Splash Intro] (JMonkey Engine splash intro) for JME games last year and nobody had to contest about it. I think the license refers to using the name of JMonkeyEngine to promote your game or to pretend it’s linked to JMonkey community.
“Powered by jMonkeyEngine” is ok as it’s plain truth
This just prevent you to state “this game was made by the jme team” or “this game is the favorite of the JME team” whereas it’s a puppy killing game…
Though you’d have your chance for the “written permission” with a puppy killing game…
en·dorse
inˈdôrs,enˈdôrs/
verb
1. declare one's public approval or support of.
"the report was endorsed by the college"
And:
pro·mote
prəˈmōt/
verb
1. further the progress of (something, especially a cause, venture, or aim); support
or actively encourage.
So as Nehon says, you can’t say things like:
“jMonkeyEngine’s official game”
Or:
“jMonkeyEngine recommends you try this game”
Or:
“Paul Speed says this game is the bee’s knees.”
ie: using the name of JME or its contributors to ‘promote’ or ‘endorse’ your game. (without permission)
Simply mentioning what it’s made with is none of those things. It’s the other way around. You are promoting and endorsing US by mentioning us in your splash screen. And that’s just fine with us.
If it helps remember it, a restaurant might say “We proudly serve Coke products.” That’s not Coke endorsing the restaurant.
Edit: though if your game really is the “bee’s knees” then I will happily declare it.