Thank you Danny and Anitha. With your help I got 1 big step closer. I was able to find my record thusly:
myinstance.sandbox.operations.dynamics.com/?mi=SysTableBrowser&prt=initial&limitednav=true&TableName=DocuRef&cmp=MEX (and then I filtered by the 'Name' column and found my exact record)
But now I need to find that same record via OData query, but I cannot find the entity record that correlates with the DocuRef table. For example, if there was an entity named DocuRef then I should be able to query it thusly:
myinstance.sandbox.operations.dynamics.com/data/DocuRefs?$top=1
The message "No route data was found" means that entity doesn't exist. Any idea what the entity is actually named, or how I could discover that?