This read-create FcList is a bitmap describing which zones with IDs 2049 through 4096, as identified by zoneIndex in the zoneTable, belong to this zone set on this VSAN, with a '1' bit meaning that zone is a member and the empty string as the default. It's a compact way for management tools to see zone set membership across this specific ID range without querying thousands of individual rows. For example, software building a report of which zones are in a zone set decodes this bitmap to identify zones in the 2049-4096 range that carry a '1' bit.