"Unused addresses" list lacks description/link to it/tooltip

[slrslr]

In oxen-electron-wallet-1.8.1-linux.AppImage , "Receive" section i can see the list of 10 "Unused addresses".
For a newbie like me, it is not apparent what are these, how and why appeared or if they can afford to send precious money to these and why it is good to use it. "Unused" is not found at:

https://docs.oxen.io/oxen-docs/using-the-oxen-blockchain/oxen-wallet-guides?q=Unused
https://github.com/oxen-io/oxen-docs-gitbook/blob/master/using-the-oxen-blockchain/oxen-wallet-guides/gui-wallet-quickstart.md

I would like to see some tooltip help icon or something like that so i know basics about this or even with a permalink to some always online/up to date resource for details.

Maybe related: https://monerodocs.org/public-address/subaddress/