Public domain allows you to do whatever you want with the work. GPL requires derivative works to also be GPL’d.
As a matter of law, all copyrightable work done by Federal employees as part of their job is public domain. This is yet another loss to society in the trend towards privatizing government operations.
I’m lamenting the fact that by contracting out work to private companies, the government-sponsored work product belongs to the private companies and not the public domain. I suspect from the part of those architecting the contracting (on both the government and private side) that this is a feature, not a bug.
If the federal government designed their own icon set it would be available for anyone to use without license restrictions. Since they’ve decided to use someone else’s icon system, they aren’t making a public domain set of icons.
But also, since they’ve decided to use someone else’s icon system, taxpayers are not paying for yet another icon system, when an existing one under an Apache license is available.
This is true. In some ways, Apache/MIT licensing is superior to public domain licensing as some jurisdictions (Germany, IIRC) don’t recognize public domain as a status.
