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The server can now keep your file list as a small index plus chunks of at most 4 MiB, so a coming browser and command-line tool can save one chunk instead of the whole list after each change.
Every account may hold 16 chunks, 64 MiB of encrypted list, and one more for every 10,000 files the storage network has confirmed, so a list naming files nobody stored buys no room. The server sees only how many chunks you hold and how large each is; what is in them stays encrypted in your browser. Nothing changes for you in this version: today's browser and tool still save the list in one piece, and the chunked form arrives with them in a coming version.