Undo

`Command` + `Z`

All hotkeys for Firefox (MacOS)

Navigation Controls Open Home Page	`Option` + `Home`
Navigation Controls Open Home Page in New Tab	`Command` + `Home`
Navigation Controls Back one Page	`Command` + `Left Arrow`
Navigation Controls Previous Page in New Tab	`Command` + `Back`
Navigation Controls Forward one Page	`Command` + `Right Arrow`
Navigation Controls Next Page in New Tab	`Command` + `Forward`
Navigation Controls Open Link/Bookmark	`Return`
Navigation Controls Open Link/Bookmark in new Foreground Tab	`Command` + `Return` / `Command` + `Click`
Navigation Controls Open Link/Bookmark in new Foreground Tab	`Command` + `Shift` + `Click`
Navigation Controls Open Link/Bookmark	`Shift` + `Return`
Navigation Controls in New Window	`Shift` + `Click`
Navigation Controls Save Link Target As	`Option` + `Return`
Navigation Controls Caret Browsing	`F7`
Navigation Controls Go Down One Line	`Down Arrow`
Navigation Controls Go Up One Line	`Up Arrow`
Navigation Controls Go Down One Screen	`PgDn`
Navigation Controls	`Spacebar`
Navigation Controls Go Up One Screen	`PgUp`
Navigation Controls	`Shift` + `Spacebar`
Navigation Controls Go to Bottom of Page	`End`
Navigation Controls Go to Top of Page	`Home`
Navigation Controls Move to Next Frame	`F6`
Navigation Controls Move to Previous Frame	`Shift` + `F6`
Navigation Controls Move Focus to Next Actionable Item	`Tab`
Navigation Controls Move Focus to Previous Actionable Item	`Shift` + `Tab`
Page Manipulation Full Screen (toggle)	`Command` + `Shift` + `F8`
Page Manipulation Zoom In/Zoom Out	`Command` + `+` / `Command` + `-`
Page Manipulation Default Zoom Level 2	`Command` + `0`
Page Manipulation Print	`Command` + `P`
Page Manipulation Reload Page	`F5` / `Command` + `R`
Page Manipulation Force Reload Page (override cache)	`Command` + `F5` / `Shift` + `Reload` / `Command` + `Shift` + `R`
Page Manipulation Stop Loading	`Esc`
Page Manipulation Save Page As	`Command` + `S`
Page Manipulation Open File	`Command` + `O`
Page Manipulation Page Source	`Command` + `U`
Page Manipulation Page Info	`Command` + `I`
Page Manipulation
General Browser Controls Help	`Command` + `Shift` + `?`
General Browser Controls Add Bookmark	`Command` + `D`
General Browser Controls Copy Bookmark	`Option` + `Drag`
General Browser Controls Bookmark all Tabs into a Folder	`Command` + `Shift` + `D`
General Browser Controls Organize Bookmarks	`Command` + `Shift` + `O`
General Browser Controls Bookmarks Sidebar (toggle)	`Command` + `B`
General Browser Controls Browsing History (toggle)	`Command` + `Shift` + `H`
General Browser Controls Download History	`Command` + `J`
General Browser Controls Error Console	`Command` + `Shift` + `J`
General Browser Controls Start Private Browsing (toggle)	`Command` + `Shift` + `P`
General Browser Controls Clear Recent History	`Command` + `Shift` + `Del`
General Browser Controls
Window and Tabs Open New Tab	`Command` + `T`
Window and Tabs Close Tab	`Command` + `W`
Window and Tabs Close Window if only one tab	`Command` + `F4`
Window and Tabs Undo Close Tab	`Command` + `Shift` + `T`
Window and Tabs Copy Tab	`Option` + `Drag`
Window and Tabs Next Tab	`Ctrl` + `Tab`
Window and Tabs Previous Tab	`Ctrl` + `Shift` + `Tab`
Window and Tabs Select Tab (1...8)	`Command` + `1…8`
Window and Tabs Select Last Tab	`Command` + `9`
Window and Tabs Open New Window	`Command` + `N`
Window and Tabs Close Window	`Command` + `Shift` + `W` / `Option` + `F4`
Search Bar Select Search Bar	`Command` + `K`
Search Bar Select Next Search Engine	`Command` + `Down Arrow`
Search Bar Select Previous Search Engine	`Command` + `Up Arrow`
Search Bar Open List of Search Engines	`Option` + `Down Arrow` / `Option` + `Up Arrow`
Search Bar Open Search Results in New Tab	`Option` + `Return`
Search Bar
Media Control Play/Pause (toggle)	`Spacebar`
Media Control Decrease Volume	`Down Arrow`
Media Control Increase Volume	`Up Arrow`
Media Control Mute	`Command` + `Down Arrow`
Media Control Unmute	`Command` + `Up Arrow`
Media Control Back to Beginning	`Home`
Media Control Back 10%	`Command` + `Left Arrow`
Media Control Back 15 seconds	`Left Arrow`
Media Control Forward 15 seconds	`Right Arrow`
Media Control Forward 10%	`Command` + `Right Arrow`
Media Control Forward to End	`End`
Page Search Find in This Page	`Command` + `F`
Page Search Find Again	`Command` + `G`
Page Search Find Previous	`Command` + `Shift` + `G`
Page Search Quick Find Text	`/`
Page Search Quick Find Link	`'`
Text Manipulation Select All	`Command` + `A`
Text Manipulation Cut	`Command` + `X`
Text Manipulation Copy	`Command` + `C`
Text Manipulation Paste	`Command` + `V`
Text Manipulation Delete	`Del`
Text Manipulation Undo	`Command` + `Z`
Text Manipulation Redo	`Command` + `Shift` + `Z`
Forums Select Next Entry	`Down Arrow`
Forums Select Previous Entry	`Up Arrow`
Forums Toggle Checkbox	`Spacebar`
Auto Complete Select Next Auto-Complete Entry	`Down Arrow`
Auto Complete Select Previous Auto-Complete Entry	`Up Arrow`
Auto Complete Delete Selected Auto-Complete Entry	`Del`
Location Bar Select Location Bar	`Command` + `L` / `F6`
Location Bar Complete .com Address	`Command` + `Return`
Location Bar Complete .net Address	`Shift` + `Return`
Location Bar Complete .org Address	`Command` + `Shift` + `Return`
Location Bar Open Address in New Tab	`Option` + `Return`