Hi Arne,
From your wording, I get the impression that you think you are directly
contacting developers or Mozilla employees. You are not. This is a
community support forum. The people that answer questions here are users
just like you, volunteering their time.
If you'd like to add Duck Duck Go or any site to the top sites row of
the New Tab page, hover the mouse pointer anywhere within a section of
tiles and click on the three-dot menu that appears in the upper right
corner of the section, then choose "Add Search Engine".
For more information, check out the following article:
<
https://support.mozilla.org/kb/customize-new-tab-page>
Also, don't forget that there's a search bar built into the New Tab
page! Go to Options-->Home, and check mark "Web Search".
--
Mailing list/Newsgroup moderator