Grenze Gotisch is a Blackletter version of Grenze , which has more dramatic details in certain letters.
To contribute, see github.com/Omnibus-Type/Grenze-Gotisch .
These fonts are licensed under the Open Font License .
You can use them freely in your products & projects - print or digital, commercial or otherwise. However, you can't sell the fonts on their own.
This isn't legal advice, please consider consulting a lawyer and see the full license for all details.