About the stored key -value stoted in the memory

[mathmax12]

The work is very interesting and amazing.
I have a question about the number of frame's key-value stored in the memory and used as reference.
The STM work stored all(or every 5 frames) the key-value of the past frames as reference.
In SwiftNet, is it only need one key-value and only updated when the Variation is detected?