In-browser Find and Replace functionality for editable text

Firefox only allows me to find text with Ctrl+F but there’s no option to search and replace (when the text is editable, such as in an email web editor).
I developed this tool as a Firefox add-on, but I was wondering if there are any plans to implement this natively?: https://addons.mozilla.org/en-GB/firefox/addon/find-replace-for-text-editing/

A lot of people are writing long emails or blog articles directly inside Firefox browser, so this might be a very useful feature for many… Or has this topic been discussed before?

Thanks for developing an add-on for this, @dalimil! You might want to check Bugzilla to see if this feature has been proposed or if it is on a roadmap for future release.