firefox

I you are tired of new bookmarks in Firefox 58 going in the "Other Bookmarks" folder, you can change it with the Default Bookmark Folder add-on.

To zoom pages by default in Firefox, open the about:config page via the location/address bar, and change the value of layout.css.devPixelsPerPx to fx 1.2, to zoom in 120% on all pages by default. This will also increase the size of icons and tabs, but this way you don't need an add-on for larger text on all web pages by default.

A few great add-ons for Firefox, which will improve security, download-speed and usability, and block Google WebP images:

From Firefox 57 onwards, Add-ons will stop working and be replaced with WebExtensions. One very used Add-on is Self-Destructing Cookies, but this extension will not be rewritten as a WebExtension. As a replacement you can use Cookie AutoDelete.

The Keyword field in Firefox Bookmarks can be used to create shortcuts and smart searches. For some reason, sometimes if you define a new keyword, the latest keyword will be deleted. Keeping track of your keywords is hard though, since there isn't a way to list all keywords in use...

If you type some keywords in the address bar (also known as location bar) in Firefox and press enter, it will perform a search for these words.

To change search engine, or configure the behaviour, type about:config in the location bar, and search for keyword.URL, update to match your needs.

To use the DuckDuckGo search engine:
https://duckduckgo.com/?q=

Use Google, with "I feel lucky" effect, going directly to the best matching result:
http://www.google.dk/search?ie=UTF-8&oe=UTF-8&sourceid=navclient&gfns=1&q=

Just go to the Google result page: