Firefox lets developers create keyboard shortcuts for their extension’s functions, which are hard coded or possibly configurable depending on the extension. Mozilla has added the ability to customize the keyboard shortcuts assigned by an extension in the current Firefox 66 Nightly build. This feature is long awaited by Firefox users who had to watch their people use it in Chrome since 2012. If an extension doesn’t support keyboard shortcuts, it will still list the extension but state that “There are no shortcuts for this extension”” in Firefox.”
Source: https://www.bleepingcomputer.com/news/software/firefox-66-lets-you-reconfigure-keyboard-shortcuts-for-extensions/