Hi, Julia here, the PM for the Archive Program at GitHub. Yes, you will be able to opt out of the program. One option is to make your repo private, as only active public repos will be archived. If you don’t wish to make your repo private please contact support at support.github.com.
I'm the PM at GitHub for the Archive Program. We aren't making the assumption that you will have computer. The archive will include a Tech Tree that explains in plain language the fundamentals of computer programming and how to use the material in the Arctic Code Vault. We will also include technical guides to QR decoding, file formats, character encodings, and other critical metadata so that the raw data can be converted back into source code for use by others in the future.