Modifying file without copyright under Apache 2.0

Question

I'd like to use a modified version of a certain file from an open source project that is licensed under the Apache 2.0.
The file itself doesn't contain copyright notice neither the project does.
Now, I understand from the terms of Apache 2.0 that I have to preserve copyright but what should I do if there is no copyright?
Should I add it myself? If yes, who should I specify in this copyright? The name of the project, something else?

Answer 1

The attribution requirement is in section 4(c) of the Apache 2.0 license:

c. You must retain, in the Source form of any Derivative Works that You distribute, all copyright, patent, trademark, and attribution notices from the Source form of the Work, excluding those notices that do not pertain to any part of the Derivative Works

As far as I can see, if there are no copyright notices to retain, then you are naturally not required to retain any, just as it would be in the absence of patent notices, trademark notices, or attribution notices.

I am not entirely sure how to interpret the relevancy of external copyright notices (or other notices) not included in whatever part of the work you are using. As two separate examples:

1. If an author includes copyright information on a separate download website but not within the project itself, does the obligation to "retain" extend to transplanting the notice into the project?

2. If an author includes a copyright notice within the project's README but you are only using a single file from that project, which does not include a copyright notice, are you obligated to include the notice from README in your redistribution of the single file?

I don't know the answers to these questions, but my guess is that you do not have an obligation in the first case (especially since you might have acquired the project through a completely different means anyway), but you might have an obligation in the second case. In that second case, "the work" broadly does include a copyright notice, so your distribution of some part of that work ought to include the work's copyright notice.

If the copyright notice is in a NOTICE file, then you would be required to keep that notice in the NOTICE file, per section 4(d).

Also, per section 4(b), you are required to state that you made changes to the original work. In that notice, you could opt to identify the original project, even if you don't know the original copyright holder.

In any case, if you do happen to know with certainty who the copyright holder is, and that they would not mind being identified as a copyright holder (and what name or pseudonym they would prefer) then you could add a copyright notice for them out of courtesy. (Basically, if you asked, and they said yes.) In the case of any doubt, I would respect the author's decision to be anonymous and avoid risking an erroneous or unwanted copyright notice on someone else's behalf.