How to "export the frame capture file"?

GPU Frame Capture has recently stopped working for me.
Currently, when I run it I get alert -

Unexpected Replayer Termination
Replayer terminated unexpectedly with error code 5. Please export the frame capture file then file a radar

When I'm in this state, how do I "export the frame capture file"?

"Export..." is greyed out under File menu.

I'm using Xcode 12.0.1 (12A7300) targeting Apple TV 4K running tvOS 14.0.1 (18J400).
How to "export the frame capture file"?
 
 
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