Audible WebPlayer Volume Slider

Adds a volume slider (0–100) to Audible Web Player and updates audio.volume.

Add a volume adjustment slider to the Audible web player. I considered using other extensions, but some were designed to work on all URLs even though I only needed it for “https://www.audible.co.jp/webplayer”. Plus, there's no guarantee that the source code published on GitHub matches the implementation of the published extension, which made me uneasy. That's why I built my own. Source code: https://github.com/blono/AudibleVolumeSlider Works only on https://www.audible.co.jp/webplayer. No data collection. No tracking. Just volume control — now and forever. After installation, the extension is located at: Windows: %LOCALAPPDATA%\Google\Chrome\User Data\Default\Extensions\ccjcgipcldeidnhpffklnjjpkbcgbaga Mac: ~/Library/Application Support/Google/Chrome/Default/Extensions\ccjcgipcldeidnhpffklnjjpkbcgbaga If you wish to verify whether there are any differences from the source code on GitHub or if any suspicious processing is occurring, please check the files at the above paths.