Fantastic, no longer do you have to add Sylish and ViolentMonkey to your browser, then worry about security.

The extension is security aware and transparent, active developer (!!!), and easy to write in.

Great to see a lightweight unified userscript and userstyle manager, however one major complaint is missing CSS preprocessor(whatever stylus supports) for usercsses, please consider adding!

The interface is a bit unintuitive but other than that, this addon delivers on all its promises

wish the css part was as intuitive as Stylus

How to "adapt" a script for this addon? I installed one script from greasyfork.org to download music from VK. It doesn't work and doesn't show any error messages. (Works fine in Greasemonkey).
I know that addon itself has nothing to do with that particular script, but since it links to greasyfork, I expected to have somewhat compatibility with those scripts.

Maybe there is a setting to allow script to download files? IDK. I thought so but couldn't find..
--
UPD: thanks for response! Do you mean I should create an issue on github? That script btw: https://greasyfork.org/en/scripts/38614-vk-media-downloader/code

Nice and lightweight extension, but an error occurs with the "RU AdList JS Fixes" script.

Very lightweight and very powerful but also very user friendly with good documentation. Fully deserved 5 stars.

Hello, is it possible to install user script and style from userstyles.org?

First time I create an account to write a review.

PLEASE, don't turn FireMonkey into VM or GM, we got those already.

Keep it simple AND SMALL, or provide a slim version.

Many addons started small then turned fat then died (at least for me).

All because users pressure coders to add more and more.

You can only trust code that you can read.

I only run one important user script, but it makes all the difference in the world.

At GitHub I already expressed my gratitude to the Dev @erosman, so my review below is for potential new FireMonkey' users.

It is an add-on for smart users!
FireMonkey easily replaces several other add-ons, using just 20% of the resources (RAM, CPU etc). The improvements in browser performance, security and privacy are visible.
In addition, FireMonkey is the only add-on (in its class) really Open Source, with the express commitment of the Dev not to invade privacy.
Another advantage is that FireMonkey uses the latest newest API.

Those users who don't care about performance, security, privacy, etc., and want lights, garlands, colors, glitter and fancy stuff ... FireMonkey may not be for them.

Some of the other similar add-ons have many automated functions, while in FireMonkey some are manual. At first I felt intimidated. But in less than 2 days of use, without problems I got used to everything. Today with few days of use, it seems like I have FireMonkey for years. I had practically no problems in the transition and migration of all my other add-ons/scripts (CSS & JS).
FireMonkey is a minimalist add-on, but totally powerful. Virtually any difficulty in the transition of other add-ons can be solved in FireMonkey (or at least almost solved). By the way, every excellent add-on requires a small investment of time at the beginning. But it's just a one-time-task/job.

The Dev (@erosman) is very responsive, and replies very promptly at GitHub. The few problems I found, the Dev solved them on the same day.

FireMonkey is not perfect, and it will undoubtedly have a path of evolution. But today, I can't imagine going back to use all the add-ons FireMonkey replaced.

Do you have doubts? Fears? Take a simple test!... it'll be difficult to repent.

Here I am giving 5 stars because it is the maximum, but FireMonkey deserves all the possible stars.

Attached a review from GHacks: https://www.ghacks.net/2019/09/10/firemonkey-uses-firefoxs-official-api-for-userscripts-and-userstyles/

Will be good, but right now doesn't compete with Tampermonkey. Needs easier method to install scripts than pasting in the code.

excellent. replaced both violerntmonkey and stylus for me, even imported my configs from those. only negative is the highly annoying animations/transitions in the settings of this extensions, but i can live with that as i dont plan on going into the settings very often

edit: i now found out that it takes like a second for it to change website fonts i have changed in fire monkey - this doesent occur with stylus. this is a little drawback. do you think it can be fixed? like i load a site, it loads with its original fonts, a second (or half a second) goes and it changes to the font i specified for this site in firemonkey

Very nice idea. But it doesn't allow you to install scripts or styles from the main repositories (like greasyfork.org or userstyles.org.) You would have to add them manually by copying and pasting the scripts' text I guess.

I tried importing my scripts from greasemonkey gsm folder but the one I tried (google hit hider) just returned an error.

Also don't know if it supports v4 greasemonkey scripts along with v3?

Looking forward to trying this out when these things are working.

Promising.