Every distinct wording since 2010, newest first.
July 12, 2019 · Core Set 2020
The source of an ability is the object that generated it. The source of an activated ability on the stack is the object whose ability was activated. The source of a triggered ability (other than a delayed triggered ability) on the stack, or one that has triggered and is waiting to be put on the stack, is the object whose ability triggered. To determine the source of a delayed triggered ability, see rules 603.7d–f.
February 1, 2010 · Worldwake
Modal spells and abilities may have different targeting requirements for each mode. An effect that allows a player to change the target(s) of a modal spell or ability, or to choose new targets for a modal spell or ability, doesn't allow that player to change its mode. (See rule 700.2.)