hi, which addons are they - if they are a "good citizen" they should offer a way to disable such tabs (noscript does for example)...

Or I must be blind, but I am genuinely convinced that not everyone is such a good citizen :)

Would be nice if users could have an upper-hand on such matters :)

I am referring to the following add-ons:

• • • Youtube Video and Audio Downloader***

https://addons.mozilla.org/en-US/firefox/addon/youtube-video-and-audio-dow/?src=userprofile

• • • Video DownloadHelper***

https://addons.mozilla.org/en-US/firefox/addon/video-downloadhelper/?src=ss

Didn't mean to create those dots though :P

for Youtube Video and Audio Downloader there seems to be a way: enter about:config into the firefox address bar (confirm the info message in case it shows up) & search for the preference named extensions.feca4b87-3be4-43da-a1b1-137c24220968@jetpack.welcome. double-click it and change its value to false.

Could you please explain what this does? Does it affect other add-ons? How does it affect my browsing experience for example, or installing add-ons in the future?

this is the internal setting of "Youtube Video and Audio Downloader" that controls whether it opens a new tab once it gets updated or not. changing this pref doesn't have any ramifications beyond that. for Video DownloadHelper i couldn't find a similar setting, but you could try getting in contact with their support about that matter...

Ok thank you, so is there any chance Mozilla or involved developers could introduce the feature I'm looking for? Or do you know where I should be to ask such features?

this might be a small nuisance for some users, but i don't think mozilla would do something against it, since it isn't breaching any addon developer guidelines...

in fact, mozilla opening a new tab after some of the firefox updates itself, in order to turn that off see: https://support.mozilla.org/en-US/kb/how-stop-firefox-making-automatic-connections#w_whats-new-page

if you'd like to start a discussion about this neverteheless, then the best place to do so would be the addons forum at https://discourse.mozilla-community.org/c/add-ons where staff and reviewers from addons.mozilla.org are participating as well.