"durational equivalent" name?

[dircknagy]

Hi all

What is this called? (see attached image)

I would call it a "rhythmic equivalent" or "durational equivalent", but i can't find it under these names in notation software manuals.

thanks!
dirck

Screen Shot 2025-06-11 at 8.52.54 AM.png (7.36 KiB) Viewed 203 times

[hautbois baryton]

Probably something close to "metric modulation," though in the case above it's showing that the half note remains the same tempo.