This document points to the older implementations in Nessie. They don't exist anymore. We will be updating it once the new implementation is merged (very soon)
b) I'm facing a challenge that relatively frequent commit interval in Flink results in a lot of small files (both data and manifest files)
You can use the Iceberg's flink action for compaction. (it compacts the small files and creates new manifests)https://iceberg.apache.org/docs/latest/flink/#rewrite-files-action
Note that old files are cleaned using the expire_snapshots and remove_orphan files procedure in Iceberg.
But they are not branch/tag aware. Hence, you must not use them.We are in the process of reviewing and splitting the PR for a merge for a "Nessie-based GC (to delete unreferenced files) CLI tool"
Once it is merged, you can use this tool for removing old/expired files from storage safely.
c) Your contributions are welcome!