dc=tools
Every character of dSHeuristics is a separate forest-wide setting. Decode one, or tick settings to build a value AD will accept. Everything runs in your browser, so nothing you paste leaves your machine. The page's Content-Security-Policy also stops it from sending anything, which you can check in its source.
Each character position is a separate setting. When the string reaches the 10th, 20th or 30th character, that character must be 1, 2 or 3, and AD refuses the write otherwise. The attribute lives on CN=Directory Service,CN=Windows NT,CN=Services,CN=Configuration,… and applies to the whole forest.