What does Select Range icon in the chart header do (in Edit mode)?

[Siakan]

I could neither find any documentation for the Select Range icon in chart headers (time series, area chart), nor find any use for. Whether it's on or off, nothing can be selected on the chart (whether in classic or modern charts).

Does anyone know what this icon/feature does or is supposed to do?

Here's a Loom on what I've tried to figure out what it does.

https://www.loom.com/share/ca8b880d76b445b283f0a63057689ddc?sid=b0d06230-57e7-4bb3-bbb6-40296754a91d