Convenience Toolkit от biggamehunter

Convenience Toolkit puts the browser tweaks you reach for most in one toolbar popup.

Tab volume: Boost or lower the volume of any tab from 0 to 500%, with a mute button and quick presets.

Video speed: Set playback from 0.25× to 4× on any video or audio player, with presets for common speeds.

Picture-in-picture: Pop a video into a floating, always-on-top window and send it back with one shortcut. Requires Firefox 151 or newer.

Mute other tabs: Silence every other tab that’s playing sound. It follows you as you switch tabs, and turning it off only unmutes the tabs it muted.

Dark and high-contrast modes: Make any page dark or high-contrast, remembered separately for each site.

Keyboard shortcuts: Alt+Shift+P picture-in-picture (press while on the page), Alt+Shift+M mute other tabs, Alt+Shift+D dark mode, Alt+Shift+↑/↓ volume, Alt+Shift+,/. speed. All except picture-in-picture can be changed under Manage Extension Shortcuts.

Privacy: No data is collected or sent anywhere. The only thing stored is your per-site appearance choices, on your own device.

Notes: Boosting above 100% may need one click on the page before it starts. Some protected videos can’t be boosted. Browser pages such as about: and the Firefox add-ons site can’t be modified by any extension.