Same gap as the remote_storage S3 client: filer.replicate uploads via
s3manager.Uploader without populating ContentType, so replicated objects
on S3-compatible backends (e.g. Backblaze B2) store binary/octet-stream
and browsers refuse to render HTML, CSS, etc.
Pass entry.Attributes.Mime through to UploadInput.ContentType, leaving
the header unset when no Mime is recorded so the remote keeps its own
default.
Chris Lu
3d4bef39dd