The site has no contact information to answer the author’s question. The answer is using rails credentials:diff --enroll which tells git to decrypt the file before performing the auto-merge.

Relevant stackoverflow: https://stackoverflow.com/a/66216056

@DCUNNING: Since this is a corporate article, there is a “* One of the available solutions is using occson.” line at the bottom. So I believe the author does not really want to know the non-occson way to resolve the issue :) But if you’re really willing to contact him - try clicking the “Contact us” link at the bottom of the page (this will practically send email to the author because it is a one-man company), or check the email information from https://github.com/tkowalewski/harvest-gtk/commit/706b4a17aaee3cde33f4252dfab39897cc64ee9e.patch OR http://tkowalewski.pl/