Compressed uploads

The 15 MB limit is on the uploaded manifest file, checked after the request is received. To submit a manifest whose JSON is larger than 15 MB, upload it as a compressed file - the server expands it, up to 100 MB decompressed. Compress the manifest file (this is how you exceed 15 MB of JSON). Upload as .zip, .zstd, or .zst instead of raw .json; the format is chosen from the file extension. For .zip, the archive must contain a .json entry (the first one found is used). For .zstd/.zst, compress the manifest.json bytes directly (single stream, not an archive). The uploaded file must be ≤ 15 MB and expand to ≤ 100 MB. No extra headers required. Compress the request body (transport).

Independently, the whole body may be sent with Content-Encoding: gzip | deflate | br | zstd; the server decompresses it transparently. This saves bandwidth only - it does not raise the 15 MB manifest-file limit (the file size is measured after decompression). Don't use it to fit a larger manifest; use .zip for that. Limits: uploaded file ≤ 15 MB, decompressed manifest content ≤ 100 MB. Exceeding either → 413.