Freda D. Cuevaswow, lost it all.
Bluegriffen is a stand alone (on your system/unless your admin knows how to run it up online) HTML/CSS editor with code view and what you see is what you get view built on Mozilla engine, as to what else can do ….
Firefox uses the Quantum engine now and is coded in Rust. Think changes are coming again as to what I have read. More slowly than the big leap from version 57 when I used to do Firefox Support.
Firefox Plugins, I mentioned that as read it in that Wiki URL supplied, search here : https://addons.mozilla.org/en-CA/firefox/extensions/ seems to be lots.
May want Firefox Developer Edition (backup your bookmarks if running both, especially if uninstall as they share) https://www.mozilla.org/en-CA/firefox/developer/
Can not go wrong developing HTML/CSS if you check your pages you made with who makes the world code standards : HTML Checker : https://validator.w3.org/ CSS Checker : https://jigsaw.w3.org/css-validator/ Some programs have this built in to send page or check page from inside the program.
Code school : https://www.w3schools.com/
What I use to have bookmarked is out of date, but google search term : Online web browser emulator
This is 1 from the list : https://www.browserling.com/ as free a little limited but can check against a wack of OS versions, and browser versions and maker.
