looks like this hunk shouldn't be here, it seem to be including a #backup_file# in the diff

there seems to be a couple of naming inconsistencies in this function:

1. the plural, which is not used in other functions that yield multiple contents (e.g., get_unarchived_content_batch)
2. the lack of trailing _id, whereas the function does return IDs and not actual content

so perhaps it should be renamed to _get_unarchived_content_id (?)

Note: I haven't checked the complete version of the file, so it might be in need of a more general swipe of naming uniformation.

• "starting after" -> "starting at"
• you should specify if previous_content is included or excluded when restarting from a previous point
• given we're talking paging, you should specify in which order the contents are returned

More generally, I suggest to use a more consist terminology for pagination: the SQL LIMIT/OFFSET paradigm seems to be a good example to follow here. How about: limit=1000, offset=None (i.e., also dropping the trailing "_content" from the offset argument)?

this seems to be a left over

same comments about the function prototype as above

Good point.
Then, as a last change (pun, intended), I propose to rename "previous_content" to "last_content". It's more appropriate, and note how you describe the meaning of the "previous_content" argument invariable as "*last* content retrieved" :-)