The location of the jump list tasks in Windows

When you right-click some programs on the task bar in Windows 7 or newer, some application-specific things can appear, like "New tab" for browsers. The interesting thing is that those menu items appear even if the program is pinned but not running, so Explorer can't ask it what things it wants on its jump list. Therefore, the items have to be stored somewhere, and that somewhere is:

%APPDATA%\Microsoft\Windows\Recent\CustomDestinations

(There's a similar folder called AutomaticDestinations under the Recent folder that has the entries for non-pinned things.) The files are proprietary and not documented anywhere I can find, but removing them definitely empties the special entries for pinned icons.