So I did figure out the issue: selecting Analyze in Excel on Firefox Developer Edition failed to open the resulting link in an expected way.
The alternative was to save the provided file (rather than open it in anything), which then allowed the service to give the proper download.
I realize the issue is odd, and hard to describe, but basically here's what happens:
After clicking Analyze in Excel, you're provided with a file prompt for the ODC file.
Open with: Excel provides a corrupted workbook with no data.
Open with: any browser provides only a text page with a connection string.
Solution:
Select Save File, then open your downloads file location and only THEN can you open this file in Excel.
If you avoid actually saving the file, the resulting file is an *.ods.htm file that is only textual in nature.
Here's an example of what not to do if you're using Firefox:
