Upload a custom sample file

Upload a file to serve as the downloadable sample file shown to end users in the importer's upload pane. When set, this file replaces the sample file that OneSchema otherwise auto-generates from the template's columns. Subject to a 5 MiB file size limit. Accepted extensions: .xlsx, .xls, .xlsm, .xlsb, .csv. Requires multipart/form-data with a single file field.