Theme

What it does: customize how the app looks — colors and accent — so it's comfortable for your eyes and your setup. Separately, a display-size control scales the whole UI (Very compact / Compact / Normal / Large … up to Maximum): go compact to pack more on screen, or larger for readability. Your choice is remembered.

Safe to run: yes. It only changes appearance, nothing on the network.

Reading results: n/a. Custom themes are saved with your work and are included in Back up & restore, so your look comes across to a new machine.