When reporting problems with the SQL Developer Extension, you will be frequently asked to ‘provide a log’ or ‘bump logging to trace, and share the output.’
What does that mean, exactly?
VS Code has an Output panel.
This contains the output from everything running in the VS Code instance, including our extension. If our backend server is having problems, they will be reported here.

To set the logging level to TRACE (the highest, most verbose setting), open VS Code settings.
Jump to extensions, and the SQL Developer section.
On the first page -

You can optionally configure the logs to be written to a file. Either way, we need to output generated by the extension.
In many cases, it will be best to restart the extension/vs code, so you can capture everything. Or, for a very simple situation, clear the log, then do the action that doesn't work, then capture the log.