The service itself is great! Some sites unfortunately don't allow mozmail.com domains, but all that do work great! So far, the forwarding always worked perfectly!
Just the integration and auto-fill sometimes interfers with the website GUI, so I disabled that for now.

Worked okay for a few weeks now most of my emails are not being delivered to my inbox that use the relay address! Can't delete it either!

Clicking the addon button in browser brings up an Ad page for Relay, VPN, etc. To even see your Relay email, you have to click "Manage all masks" just to bring up a link to relay site on another tab. You can't even copy and paste from the Add on button because your mozmail emails are not even displayed.

Works fine for me and serves it's purpose. Lots of people down-voting or crying about it but probably still use FB. The process is simple, most of the problems are user specific or can't read instructions. The only thing I don't like is the addon button does nothing, doesn't even show you your mask, just a giant ad in the middle. You still have to click away to another site to copy and paste. The relay auto detect for field is also hit or miss. As far as getting emails relayed, works well and I haven't had issues

harika

Gold app...

很好用，提供了一个更方便可信的马甲邮箱来源，可惜免费版不提供拦截营销邮件的服务。
另外建议加个单独设置每个马甲邮箱转发目标的功能
Perfect. It provides a more convenient and reliable source of aliase email. Unfortunately, the free version does not provide the service of intercepting marketing emalis.
In addition, I recommend to add a function to separately set the forwarding target of each aliase.

Good idea, but in general it's pretty useless as you can't switch your main email address to another one or even better using more email addresses.
So, if I don't want to use my main email address I can uninstall.
Also, premium is still not available here in Czech Republic which will probably be fixed in the future.

edit: I already removed extension for not being usable for me as I don't want to use my main email address.

how do i remove context menu??

There isn't a critical mass of users, so websites are already starting to block this domain. iCloud on the other hand has the critical mass and no one will dare to block their domain.
This should be a feature of an email provider. Although Mozilla attempting to be a privacy provider, these products are half-baked and quite a commitment on their part while the project may not last.

UPDATE I am giving this three stars because I have great hope it but believe it is too expensive for the FireFox spirit. I did have a problem when a logon page appears where I already have an account and FireFox Relay would not let me enter my actual email address to log in. I tried settings in FireFox add-on list and looked online for a support page with a solution; then I had to download an authenticator app on my phone to even make this comment which sparked a developer response that solved my problem! The solution, though, removes the helpful icon from every page where I might want to use it to create the temporary screen email. While I was looking at the solution (which was at a location not intuitive to me), I found another default setting to change.