The built-in Firefox home page has little (or sometimes not so little) messages that appear below the search box. These "snippets" changes from time to time. If you see a message you want to remove from the rotation, hover your mouse over it and click the "X" button in the upper right corner. I'm attaching a screenshot example.

Does that help?

You could also check out about:blank if you want.

If you prefer not to see snippets on the about:home page or if there are problems with a snippet then you can set this pref to an empty string value on the about:config page by deleting the current value via the right-click context menu (Modify) or a double-click.

• browser.aboutHomeSnippets.updateUrl (delete current value)

Delete the storage\persistent\moz-safe-about+home folder in the Firefox profile folder with Firefox closed ("3-bar" Firefox menu button -> Exit/Quit) to remove snippets stored in IndexedDB and make Firefox use a default snippet set.

You can reset the browser.aboutHomeSnippets.updateUrl pref via the right-click context menu to the default value to re-enable the snippets and make Firefox recreate the moz-safe-about+home folder.

Close and restart Firefox after changing the value of the browser.aboutHomeSnippets.updateUrl pref.

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Managed to follow the guide and remove the snippets! Thank you very much!