zlacker

No it is not. There is no license in that repository.

Relevant: https://github.com/orgs/community/discussions/82431

> When you make a creative work (which includes code), the work is under exclusive copyright by default. Unless you include a license that specifies otherwise, nobody else can copy, distribute, or modify your work without being at risk of take-downs, shake-downs, or litigation. Once the work has other contributors (each a copyright holder), “nobody” starts including you.

https://choosealicense.com/no-permission/

>>jasonj+(OP)
There is a license: https://github.com/djyt/cannonball/blob/master/docs/license....

...but it's very clearly not an open source license.