What is ⌥ Opt + ← keyboard shortcut for?

Google Chrome (macOS) - Move your cursor to the beginning of the previous word in a text field  

Apple macOS - Move the insertion point to the beginning of the previous word  

Apple iBooks - Move to the beginning of the current or previous word  

Apple iBooks - Add a column to the left of the selected cells  

Google Docs (macOS) - Rotate counterclockwise by 15°  

Ace Editor (Mac) - Go to word left  

Adobe Premiere Pro (Mac) - Trim Backward  

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

Adobe Premiere Pro (Mac) - Trim Backward by One Frame  

DaVinci Resolve 15 (Mac) - One subframe reverse  

Final Cut Pro X - Move the playhead to the previous field in an interlaced clip  

Substance Painter (Mac) - Camera rotate  

zsh (macOS) - Move the cursor one word backward  

WireShark 3.4.3 (macOS) - Go to the previous packet in your selection history  

CodeMirror - Move to the left of the group before the cursor. A group is a stretch of word characters, a stretch of punctuation characters, a newline, or a stretch of more than one whitespace character  

Mode SQL Editor (Mac) - Go to word left  

AWS Cloud9 IDE (Mac) - Goto Word Left  

Nuclide (Mac) - Collapse all the directories to the top parent.  

Coda for iOS - Move to the beginning of the current word  

Adobe Dreamweaver 20.2 (macOS) - Move word left  

Valentina Studio - Move Word Left  

QuickTime Player (macOS) - Go to the beginning of a movie  

EyeTV - (tap once) Single Frame Backward  

Total War: Attila (Mac) - Both rotate left  

Twitterrific 6 - Show thread participants  

Apple Pages - Move to the left edge of the current word (works for left-to-right and right-to-left text)  

Apple Pages - Add a column to the left of the selected cells  

Guitar Pro 8 (macOS) - Step backward  

Adobe Experience Manager 6.4 (macOS) - Move the cursor to the beginning of the previous word  

iPad Smart Keyboard - Move cursor one word to the left  

Salesforce - (macOS) Go to word left  

Salesforce - (macOS) Go to word left  

ConnectWise 2018.6 - Navigate back  

RX 8 Audio Editor (macOS) - arrow   Move playhead to previous marker or selection boundary  

Nuendo 10 (macOS) - Start left