[zaphirplane]

To be clear, do the files contains a copyright or licence, if they do not and many companies don’t attach a copyright header to their files. Why would the assumption be that the files are not public domain or free for use

[dodobirdlord]

Because unless otherwise stated, they just aren't.

[colejohnson66]

Copyright law in the US grants a copyright to all works without an application (so not the same as a patent)