If you’re using KDE, apparently changing your system application style might help - Breeze, for example, has an option for visible scroll arrows. Link.

In any case, it’s a GTK thing, not a LibreOffice thing.

This strikes me as an odd comment. Did you have a specific reason to expect that 26.2 would include this, such as an enhancement request that you’d logged (or had been following) via their community channels?

<username> is not in the donors file. This incident will be reported.

Also, I’m curious about the UI refinement.

In the release notes you’ve linked, there’s a heading called User Interface. It’s a fair number of small QOL improvements.