What are some of your must have browser extensions?

I recently made an effort to switch to Firefox, and now I'm looking for some good browser extensions to make my web browsing experience better. Here are the ones I currently use:

• HTTPS Everywhere
• Privacy Badger
• uBlock Origin
• Vimium

I was browsing r/privacy today and I came across this guy going on about how Mozilla was just pretending to be privacy focused. Here's his comment. Now I don't really know what to think of this, and frankly, I'm getting really exhausted of hearing about how all the things I'm using aren't actually trustworthy. So can so someone put my mind to rest? Does this guy's claims have any truth to them? Thanks.

Here is what just happened to me:
Firefox installed two addons - fxmonitor@mozilla.org.xpi and telemetry-coverage-bug1487578@mozilla.org into my browser silently, even though I've explicitly turned all the telemetry off.
This have happened before, and Mozilla apologized for it, however it seems that they learned nothing and are willing to do so again.
There goes the last scrap of my trust into Firefox. I suggest you check your browsers too.

Hi, I've started developing syntax highlighting, but I'm unable to connect to Tildes on localhost. It's running, I can connect to Prometheus, but not to Tildes. I use Ubuntu.

I know there are few people here who already contributed to Tildes, how do you connect to Tildes?

• Firefox shows Secure Connection Failed, even after adding exception in about:config for domains localhost, *, 127.0.0.1, both with and without port, I even tried adding https:// before them.
• Qutebrowser displays nothing
• Chromium displays ERR_CONNECTION_RESET (not something like insecure connection)
• Chrome displays ERR_CONNECTION_RESET (not something like insecure connection)
• Curl displays OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to localhost:4443
• wget displays Unable to establish SSL connection.
• lynx displays Unable to connect to remote host.

Could someone tell me how to config Firefox / install certificate for Tildes on localhost / move Tildes to http?

Thank you

Edit: I tried setting firefox security exception in a different way and this happened.

I mainly use my keyboard to navigate around in Firefox so decided to edit UserChrome.css to create a custom, ultra-minimalist "one line" UI for myself and also maximize my screen real-estate by removing the window Titlebar and Tab Bar (using Tree Tabs sidebar extension instead). I also dislike how cluttered the Firefox interface is with unneeded options scattered everywhere, and how much redundancy there is with many options showing up in multiple places for no good reason, so I removed most of that as well. Here is the results:

Main UI (Navigation and "Hamburger" toolbar buttons removed)
Tree Tabs sidebar & More Tools both open
"Find in page" moved to the top, with Menu bar also toggled on
New Tab Page (my Bookmark Toolbar auto-unhides itself only on this page)
My Home Page, set to the FF Library "popout" page (chrome://browser/content/places/places.xul)

Context Menus (with lots of redundant and unused options removed):
Address bar dropdown
Page context menu
Image context menu
Link context menu

If anyone is interested in trying it out themselves, here is the UserChrome.css (which needs to go in the /chrome directory of your Firefox profile).

And if enough people are interested in learning Firefox UserChrome.css customization using the Browser Toolbox with remote debugging, I can always write up a tutorial at some point. There are some decent resources already available over at userchrome.org and reddit.com/r/FirefoxCSS/ too.