This is a "feature" called "!Bang"... as documented here: here and here. There is nothing special about this string (try cutting it down), aside from the very first \.
Specifically giving a ! or \ at the beginning of your query will have a special effect... ! goes to a registered site for quick access, while \ goes to the first search result.
A couple of ...
The redirect from the regular start page states:
Clear your cookies often? Try our homepage that never shows these messages: start.duckduckgo.com
...this implies that the regular homepage sets a cookie to hide messages the next time you visit, while the "start" page just never displays them.
According to an official DDG support representative on the DDG ...
Yes you can - it is the same syntax.
You can add site:domain to your search to restrict the results to a particular domain, e.g. duckduckgo site:gabrielweinberg.com.
Click the site icons next to the results (on the left) to do a site search for the domain related to that result. You can also do the same
by clicking the 'More ...
This help page explains the situation best:
Our intention is to not auto-correct searches. That is, we intend to
completely respect the query you type in, and (in some cases) display
a 'Did you mean?' link at the top when relevant.
However, there are a few outstanding major bugs in this area that we
are working to resolve. As a result, you may ...
The "DuckDuckGo Settings" are available over HTTP (without SSL/TLS) at:
...as any other page of DuckDuckGo with kh=-1 parameter.
And on a "Privacy" tab of the settings page you can change the "HTTPS" setting ("Use encrypted version of the site") to "Off" value and save it in a cookie.
If you're using the Chrome Browser, Goole has released the Personal Blocklist extension
The personal blocklist extension will transmit to Google the patterns
that you choose to block. When you choose to block or unblock a
pattern, the extension will also transmit to Google the URL of the web
page on which the blocked or unblocked search results are ...
When going to the Goodies and selecting the "programming" option, the following can be seen:
If you edit the field where "6GB/700KB/s in min" is mentioned and change it to "15GB/600KB/s in hour", then the following can bee seen:
So then if you type that in the main DDG search field, you get this:
With a standard URL rewrite/redirect pattern, you could use a Greasemonkey/Tampermonkey/generic userscript like:
// @name DuckDuckGo, Always add certain search parameters
// @match *://*.duckduckgo.com/*
// @run-at document-start
// @grant none
//--- SET THIS NEXT VARIABLE TO TASTE.
When you search through Images automatically shows more results when you scroll down:
If more results are not loading automatically, there might be a button Show More for laoding more results for images.
You can toggle this settings from DuckDuckGo Settings:
Enabling Auto-Load will show you more results as you scroll-down and disabling it will ...
There does not seem to be a way to look at all of the bangs, mostly likely due to the large number of them (over 7,000), nor is there a way to view any data about them, as far as I'm aware. To modify it, you may want to try posting a new bang and explaining in the comments that it is an update.