The file you asked about can be found in the documents bundle that comes as part of the order whenever you order at least one file from a particular cruise. FYI, all files listed in "/documents=" as well as "/calibration_files=" should be present in the relevant documents bundle.
There are a couple ways to get this documents bundle that contains the calibration file you're looking for.
1) Use the ordering system
. If you use the ordering system to order a SeaBASS file, the order will always include the relevant documents folder. Once you unpack your order, it will create a directory structure that mimics how the dataset is organized in SeaBASS. The documents bundle will be found up one or more directory levels from the data file. Typically it is parallel to the relevant "archive" data folder. There are some exceptions where the documents bundle is found up more than one directory level.
2) Browse Archive
. If you're browsing to the archive (e.g., perusing the archive, or looking at the table of data files just prior to ordering the data) you will be able to find a direct download link to the documents bundle. (e.g., 9237990448_documents.tgz
Just FYI, the associated file bundle you mentioned contains special files or ancillary metadata that are considered optional for most users, which is why users must opt in with the "include all associated files" option. Sometimes calibration files could be part of this. However, you only need to look for ancillary files in the associated bundle if a SeaBASS data file (.sb) contains the metadata header (or the field) called "associated_files" and it lists a file you are interested in.