See https://docs.github.com/en/rest/reference/repos#get-a-commit

If there are more than 300 files in the commit diff, the response will include pagination link headers for the remaining files, up to a limit of 3000 files. Each page contains the static commit information, and the only changes are to the file listing.

It's an odd case. Only the "files" key array will be paginated, but unlike the other endpoints that paginate that return an object instead of an array, this one will include lots of other keys. I'm not sure if that case is covered by https://github.com/octokit/plugin-paginate-rest.js/blob/92ed1aab99fe8045fe2c23b21308390471d0c8f5/src/normalize-paginated-list-response.ts

If someone would like to give this a go, I'd be happy to advice. Comment below if you have any questions. The first step would be to add a test to https://github.com/octokit/plugin-paginate-rest.js/blob/master/test/paginate.test.ts, then start a pull request. We can continue the discussion there