Some settings for Firefox cannot be adjusted in the normal way (via the “Settings” menu item).
Remove service workers
Open about:debugging#/runtime/this-firefox in the address bar.
Delete all listed service workers by enteringfor (let button of document.querySelectorAll(".qa-unregister-button")) { button.click(); }
in the debugger console.
More than 4 rows of top sites on start page
Open about:config in the address bar.
Enter browser.newtabpage.activity-stream.topSitesRows in the search field.
Enter the desired number of rows.
Keep backspace key from going back to previous page
Open about:config in the address bar.
Enter browser.backspace_action in the search field.
Set the value to 2 to unmap the backspace key.
Customise/hide elements on websites
In the user folder
MacOS: /Users/[user name]/Library/Application Support/Firefox/Profiles/[profile-id].default-release/
Create a subfolder “chrome” (if it does not already exist) and create a file “userContent.css” there.
In this file, define styles for elements on defined domains, e.g.@-moz-document domain(www.ex-parrot.de) {
.sample-class {
display: none !important;
}
#sample-id {
font-weight: bold !important;
}
}