Full details of the build including source code and schematics is in my project notebook on GitHub - see LEAP#589.
After studying various clips and searching fruitlessly for any definitive information, my conclusion:
- the basic pattern is "Fl W 1.7s" - white flash every 1.7 seconds. On-time is approximately 0.2 seconds
- however the pattern is often broken as the scene cuts away. I write this off as 20th century editing quirks!
For simplicity, I burned this flash pattern into a DIP8 ATTiny85 and used that as the "bridge" of a freeform shuttle.
Here's a quick demo..