What is ⌥ Opt + ↓ keyboard shortcut for?

Firefox (macOS) - (after you have written something in the address bar) Switch Search Engine  

Firefox (macOS) - (when the Search bar is focused) View menu to switch, add or manage search engines  

Apple iBooks - Arrow Move to the end of the current paragraph  

Apple iBooks - Add a row below the selected cells  

Capacities.io (Windows) - Move selected blocks down  

Notability - Go to next view  

Ace Editor (Mac) - Move lines down  

Capacities.io (Mac) - Move active block down  

Capacities.io (Mac) - Move selected blocks down  

Final Cut Pro X - Nudge down the value of the selected keyframe in the animation editor  

Adobe Premiere Pro (Mac) - Decrease Leading by One Unit  

Penpot (Mac) - Decrease letter spacing  

AWS Cloud9 IDE (Mac) - Move Lines Down  

Looker 6.8 (Mac) - Move current or selected lines down  

Mode SQL Editor (Mac) - Move lines down  

Mode SQL Editor (Mac) - Move lines down  

GitLab (macOS) - Move line down  

QuickTime Player (macOS) - Turn the volume down to the minimum level  

Signal (macOS) - Next conversation  

iPad Smart Keyboard - Jump to next channel  

Apple GarageBand - Transpose selected notes down one semitone  

Guitar Pro 8 (macOS) - Move down  

Rekordbox 6 (macOS) - Halve the BPM value  

Things (Mac) - Scroll to bottom  

Salesforce - (macOS) Move lines down  

Salesforce - (macOS) Move lines down  

Twist (macOS) - Next sidebar  

Apple Pages - Add a row below the selected cells  

Things (iPad) - Scroll to bottom  

Desmos Graphing Calculator (macOS) - Move to next curve  

Google Looker (macOS, 2023) - Move current or selected lines down