Hi, just saw this PR and was wondering how the retention period works for "p blobs". Since blobs are deduplicated to me, it seems that the retention period is wrong in those cases (old file still used, or new file with same content as old one). AWS published a whole article on renewing retentions (https://aws.amazon.com/de/blogs/storage/maintaining-object-immutability-by-automatically-extending-amazon-s3-object-lock-retention-periods/) . How does kopia handle this correctly in GCS? From the GCS documentation versioning is independent and the retention period does not only start after the delete / overwrite, as I read it (which would be necessary for ransomware protection). Current files IMHO need period renewal of the retention period. Does Kopia really do this e.g. in maintenance (which at least would be needed)?

Sorry for high jacking this PR but there was no answer in the forums. I have the fear, that ransomware protection is not working as claimed without any better documentation . But I haven't had the chance to prove it.

Maybe the people involved in this PR can quickly comment on it (I am happy to add this to documentation if I am proven wrong).

Current files IMHO need period renewal of the retention period. Does Kopia really do this e.g. in maintenance (which at least would be needed)?

--extend-object-locks needs to be enabled as part of kopia maintenance set like with S3. I guess docs should be updated to be explicit in this & this section also needs updating to include GCS. Since here only talks about S3 but it's also required for Azure and GCS

But in order for it to work #4151 needs merging

I'll update the docs to make this more clear @riedel