1. Addons from this list of recommended extensions are safe for sure. They are reviewed by a human.
2. Any other extensions from AMO are for 99.9% safe, so I wouldn't worry so much about the safety.

Thank you for your response TyDraniu, but you gave me a link to the recommended Polish extensions???

By the way, are "Firefox Extensions" and "Firefox Add-Ons" the same thing?

Do Firefox Add-Ons get access to my personal data?

Ooops, sorry. This is a good URL: https://addons.mozilla.org/firefox/search/?recommended=true&sort=random&type=extension

Do Firefox Add-Ons get access to my personal data?

Password extensions have access to your passwords, bookmark extensions have access to your bookmarks and so on. You have to pay attention on permissions asked by an extension.

Do Firefox Add-Ons get access to my personal data?

Please also note that "having access" doesn't mean that someone can access your personal data.

Thank you for your fast response TyDraniu!

Could you tell me the safest "Firefox Extensions" that I can use so I know they're completely and perfectly safe?

You mentioned "AMO" earlier but I'm not sure what this means?

Is there a difference between "Firefox Extensions" and "Firefox Add-Ons"?

1. The link above is OK. 2. AMO = Addons.Mozilla.Org

Thank you again for your fast response TyDraniu!

So the safest place for me to install Firefox Extensions is from the recommended list from this URL? http://addons.mozilla.org/

Sorry to be asking such basic questions but I'm just super worried about installing a Firefox Extension that contains malware!

My big fear is that I'll install a "Firefox Add-On" and will be giving away access to my personal information.

Hi Helpless_Quest, I think it's very reasonable to be concerned that if you give an extension permission to access data for all sites -- which means the ability to read and change pages and whatever they display and whatever you enter into them -- the developer might use that access to do things that aren't advertised in the listing.

Beyond the Recommended program, our support article lists things to consider when installing an extension: Tips for assessing the safety of an extension.

Is there a difference between "Firefox Extensions" and "Firefox Add-Ons"?

Addons is a general term that groups together separate things as in Extensions, Themes, Plugins, Search Engines, Dictionaries, Language Packs.

NPAPI Plugins are not supported anymore except for Flash Player from Adobe but with restrictions and Adobe will be completely dropping Flash at end of 2020 anyways. Dictionaries are for the inline spell checker and language packs are for changing the UI language.

You can (should) always read the reviews of an extension to see how others report it. If there are issues then you usually see this in the comments or in only having a few stars.

Thank you very much for your replies!

I'm looking at the list of "Recommended Extensions" now.