I believe that the credit list is not a "hard" requirement. For example, the common pattern for citing Wikipedia articles is only to link to the Wikipedia page and stating that the author lists could be found here. And Wikisource contributors have a much weaker authorship relation to the content than the Wikipedia contributors. So, I guess that a rewording of the credits page might to the job (but I'm not a lawyer...).

However this contributor list was by far the top improvement request when I made the first version of WSExport. There were at this time (2012) a very strong request for it from the Wikisource community. It's why it have been introduced even if it is quite costly on the implementation side.

Yes, definitely, good point. I don't really think we should remove the contributors list; it's not all that costly, and worth having if people do like it. I mention it only as one possibility. I think we could maybe improve the querying performance – even switch to querying the DB directly? I'm not sure. But this is mostly about reducing dependencies.

A related issue:

GH182: contributors name not picked properly from proofread page only from transclusion page1
balajijagadesh commented on 10 Jun 2019:
The issue has started again. in the downloaded ebooks, the name of people who have contributed is not coming up in Tamil wikisource. The contributor list is empty.
balajijagadesh commented 15 hours ago
The problem is intermittent. Sometimes it works properly. Sometimes some of the contributors are left out.

PR: https://github.com/wikimedia/ws-export/pull/335

Merged.

PR: https://github.com/wikimedia/ws-export/pull/351

Merged again!

PR: https://github.com/wikimedia/ws-export/pull/354

Merged.

In comparison to Phetools, we have a more complete list of credits including people who contributed to subpages, images and transcluded pages (e.g. transcribed pages in the Pages namespace).

I have been comparing the credits list in exported Epubs with my own script which uses various API endpoints.

They mostly match. A few (about 5 in about 130 ebooks in 13 languages) don't match, but I cannot rule out a bug in my own script.

Test Environment: https://ws-export.wmcloud.org version 2.5.1.