"Google Search:" is 14 characters, same as "DuckDuckGoing:". That's the way I preserve structure of such strange files: I edit only "normal" text, not strange symbols, and I preserve length of normal text as it was. Thank you for file-format-name and link to specification. :-)

About the icon to the left of the words: it is inside icon theme.
/usr/share/icons/<theme>/48x48/browser_search.png

I put DuckDuckGo icon here, too ;-)

Thank you! Best wishes.
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Per aspera ad astra...