Honestly, it would be interesting if there was a little button to click on.
Because, after visiting several websites, I really can't see a little button anywhere in my browser to click. ☹️

I’ve just installed Flagfox https://addons.mozilla.org/nl/firefox/addon/flagfox/
And yes, as already mentioned by user arnofly, this works flawless,
the Flag is visible in the address bar when you open a webpage immediately after installing the extension.

All the information in one place..you can view the hosting provider,IP Address,DNS records and who-is information.excellent plug-in.

Better extension for Firefox 57+ I tried, but not as good as Flagfox

This is a perfect plugin to get the details of the hosting provider of any website. I do not need to go anywhere else to check the details. This really helps when any client is in hurry and you are in dark area to get the details. Just install this plugin and you will save your time. Many thanks to AccuWebHosting for this add-on.

It is very handy tool to get the DNS records of domain instantly.

It's exactly what I was looking for so long. It tells you web hosting provider, WHOIS information and DNS lookup of the domain. Its 3 in 1 actually. Excellent plugin, Kudos to developers.

This is a great tool to check DNS records. Exactly what i was looking for.

Quick and easy way to find out which web hosting company is hosting a particular website.

this is the exact tool which can assist me to check the domain/website details while I am on the helpdesk. Good Job..

This is exactly what I was looking for. I can get all details on who is hosting any particular site.

Best plugin to find websites information directly from the browser.