I'm not using rclone yet, but it is something we certainly see potential for. We have been a Google company for many years and I certainly received this 'developer' message as well as seeing that the links for several of my Drive files have been made more secure already!
Here is what I can see so far and it does seem to be inline with the documentation at various sites.
- This does not apply to native Google files (Docs/Sheets/Slides etc), however it does apply to folders
- It does apply to files uploaded to Drive like PDFs, PNGs, MS Office files
- It only applies to files which have been shared to everybody using a link (this means 'external' shares if you are part of gapps/gsuite/workspace etc)
- It does not apply to files shared by link within your gapps/gsuite/workspace domain
- The additional security component, the 'resourcekey', has actually been added to all files shared in this way since late 2017 (the most recent of my files that is affected is dated Oct 25, 2017)
So for most people, this only matters if you have old, non-Google files, shared by link across the Internet. Even then it will apparently only matter if the person attempting to access the file has not done so already.
I don't know exactly how rclone works, but I would expect any changes to be minimal as it appears to be interacting as a service account or impersonating an internal user, so it shouldn't ever have to worry about external shares and links.0