Starships with the Web Cloak ability will start a turn as Cloaked if they're in a Web Minefield. This cloaking will be lost if the ship ends movement outside of a web minefield or if the web minefield it's in is swept to the point where the starship is no longer within it.
The Web Cloak effect is achieved by synchronizing the starship's shields with the Web Minefield it's in, causing the starship to blend in with the Web Minefield, effectively cloaking it.
No special Mission or Friendly Code is required to activate this ability.